Diamond-Blackfan anemia pathophysiology
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Roghayeh Marandi
Keywords:RP: Ribosomal proteins, RPS: small ribosomal subunit, RPL: large ribosomal subunit, DBA: Diamond-Blackfan anemia
Overview
The exact pathogenesis of DBA is "Ribosomapathy". Mutations in ribosomal protein genes have been confirmed to be the direct cause of faulty erythropoiesis and anemia. Mutations reduce the actual numbers of ribosomes in blood precursor cells. Without enough ribosomes, the precursors can’t produce enough GATA1, so mature red cells never form. Other blood cells — like platelets, T cells, and B cells — are not affected since they’re not dependent on GATA1. Based on a documented pathogenetic hypothesis that has been named "ribosomal stress", ultimately a defective ribosome biosynthesis leads to apoptosis in those defective erythroid progenitors which in turn is leading to erythroid failure. In "ribosomal stress", reduced RP synthesis activates p53 that induces the downstream events and leads to cell cycle termination or apoptosis, leading to erythroid failure.
Pathophysiology
- The exact pathogenesis of DBA is "Ribosomapathy."
- Mutations in ribosomal protein genes is the cause of faulty erythropoiesis and anemia.[1].
| Ribosomal protein gene mutations---> Ribosomal protein Insufficiency ---> Imbalance of Ribosomal Assembly Intermediates ---> Free Ribosomal proteins bind to inhibitors of P53 and Stabilize P53 expression ---> P53 Activation ---> Cell Cycle Arrest |
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- Researchers found Ribosomal protein gene mutations reduce the actual numbers of ribosomes in blood precursor cells. Without enough ribosomes, the precursors can’t produce enough GATA1, which is essential for precursor cells to differentiate into red blood cells, so mature red cells never form.
- Based on a documented pathogenetic hypothesis which has been named " ribosomal stress ", ultimately a defective ribosome biosynthesis leads to apoptosis in those defective erythroid progenitors which in turn is leading to erythroid failure. In ‘‘ribosomal stress, reduced RP synthesis activates p53 that induces the downstream events and leads to cell cycle termination or apoptosis.[2] Finally, this phenomenon results in the DBA phenotype of anemia, deprived growth, and results in congenital abnormalities.
- Mutated RP genes in DBA encode ribosomal proteins which are involved in either the small (RPS) or large (RPL) subunits of these proteins and the scarcity of these proteins can result in the development of the disease.
- Non-Rp genes such as TSR2 and GATA1 also have an important role in the pathogenesis of DBA. TSR2 plays a role in ribosome biogenesis since it is involved in the pre-rRNA processing and binds to RPS26
- GATA1 which is the major erythroid transcription factor as being essential for precursor cells to differentiate into red blood cells and plays a critical role in regulating normal erythroid differentiation by activating of other erythroid genes.[3]
- Other blood cells — like platelets, T cells, and B cells — are not affected and can still develop since they’re not dependent on GATA1.[4][5][6][7][8]
- In the remaining 10-15% of DBA cases, no abnormal genes have yet been identified. It is likely that mutations are in a regulatory region including intronic regions and promoters in one of the known RP genes may account for the DBA phenotype. [9]
References
- ↑ Vlachos A, Dahl N, Dianzani I, Lipton JM (October 2013). "Clinical utility gene card for Diamond-Blackfan anemia--update 2013". Eur. J. Hum. Genet. 21 (10). doi:10.1038/ejhg.2013.34. PMC 3778360. PMID 23463023.
- ↑ McGowan KA, Li JZ, Park CY, Beaudry V, Tabor HK, Sabnis AJ, Zhang W, Fuchs H, de Angelis MH, Myers RM, Attardi LD, Barsh GS (August 2008). "Ribosomal mutations cause p53-mediated dark skin and pleiotropic effects". Nat. Genet. 40 (8): 963–70. doi:10.1038/ng.188. PMC 3979291. PMID 18641651.
- ↑ Lipton JM, Ellis SR (April 2009). "Diamond-Blackfan anemia: diagnosis, treatment, and molecular pathogenesis". Hematol. Oncol. Clin. North Am. 23 (2): 261–82. doi:10.1016/j.hoc.2009.01.004. PMC 2886591. PMID 19327583.
- ↑ O'Brien KA, Farrar JE, Vlachos A, Anderson SM, Tsujiura CA, Lichtenberg J, Blanc L, Atsidaftos E, Elkahloun A, An X, Ellis SR, Lipton JM, Bodine DM (June 2017). "Molecular convergence in ex vivo models of Diamond-Blackfan anemia". Blood. 129 (23): 3111–3120. doi:10.1182/blood-2017-01-760462. PMC 5465839. PMID 28377399.
- ↑ Ulirsch JC, Lareau C, Ludwig LS, Mohandas N, Nathan DG, Sankaran VG (August 2017). "Confounding in ex vivo models of Diamond-Blackfan anemia". Blood. 130 (9): 1165–1168. doi:10.1182/blood-2017-05-783191. PMC 5580274. PMID 28615220.
- ↑ Boultwood J, Pellagatti A (July 2014). "Reduced translation of GATA1 in Diamond-Blackfan anemia". Nat. Med. 20 (7): 703–4. doi:10.1038/nm.3630. PMID 24999938.
- ↑ Ludwig LS, Gazda HT, Eng JC, Eichhorn SW, Thiru P, Ghazvinian R, George TI, Gotlib JR, Beggs AH, Sieff CA, Lodish HF, Lander ES, Sankaran VG (July 2014). "Altered translation of GATA1 in Diamond-Blackfan anemia". Nat. Med. 20 (7): 748–53. doi:10.1038/nm.3557. PMC 4087046. PMID 24952648.
- ↑ Khajuria RK, Munschauer M, Ulirsch JC, Fiorini C, Ludwig LS, McFarland SK, Abdulhay NJ, Specht H, Keshishian H, Mani DR, Jovanovic M, Ellis SR, Fulco CP, Engreitz JM, Schütz S, Lian J, Gripp KW, Weinberg OK, Pinkus GS, Gehrke L, Regev A, Lander ES, Gazda HT, Lee WY, Panse VG, Carr SA, Sankaran VG (March 2018). "Ribosome Levels Selectively Regulate Translation and Lineage Commitment in Human Hematopoiesis". Cell. 173 (1): 90–103.e19. doi:10.1016/j.cell.2018.02.036. PMC 5866246. PMID 29551269.
- ↑ Da Costa L, Narla A, Mohandas N (2018). "An update on the pathogenesis and diagnosis of Diamond-Blackfan anemia". F1000Res. 7. doi:10.12688/f1000research.15542.1. PMC 6117846. PMID 30228860.