A Second Generation Transgenic Mouse Model Expressing Both Hemoglobin S (HbS) and HbS-Antilles Results in Increased Phenotypic Severity

• Published in: Blood 1995-09, Vol.86 (6), p.2419-2428
• Main Authors: Fabry, M.E., Sengupta, A., Suzuka, S.M., Costantini, F., Rubin, E.M., Hofrichter, J., Christoph, G., Manci, E., Culberson, D., Factor, S.M., Nagel, R.L.
• Format: Article
• Language: English
• Subjects: Anemia, Sickle Cell - blood; Anemia, Sickle Cell - genetics; Anemia, Sickle Cell - pathology; Anemias. Hemoglobinopathies; Animals; Biological and medical sciences; Brain - pathology; Centrifugation, Density Gradient; Crosses, Genetic; Disease Models, Animal; Diseases of red blood cells; Erythrocyte Count; Erythrocytes, Abnormal; Globins - genetics; Hematologic and hematopoietic diseases; Hemoglobin, Sickle - biosynthesis; Hemoglobin, Sickle - genetics; Hemoglobins - analysis; Hemoglobins, Abnormal - genetics; Heterozygote; Humans; Kidney - pathology; Liver - pathology; Lung - pathology; Medical sciences; Mice; Mice, Transgenic - blood; Mice, Transgenic - genetics; Organ Size; Osmolar Concentration; Phenotype; Point Mutation; Recombinant Proteins - genetics; Reticulocytes; Severity of Illness Index; Spleen - pathology; Urine - chemistry
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V86.6.2419.bloodjournal8662419

We report on a second generation of transgenic mice produced by crossing a transgenic mouse line expressing high levels of human α and βS chains (αHβS[βMDD]) with a line expressing human α and βS-Antilles (βSAnt). We hypothesized that mice expressing both hemoglobins (Hbs) would have a more severe phenotype because the reduced oxygen affinity and solubility of the βS-Antilles might enhance the rate and extent of polymer formation. We obtained mice that expressed both βS and βS-Antilles. The doubly transgenic mice that are heterozygous for deletion of mouse βMajor (βMD) occurred with reduced frequency and those that are homozygous for deletion of mouse βMajor (βMDD) occurred at a much reduced frequency and suffered early mortality. Human α was 58% of all α globin for ail animals, whereas βS and βS-Antilles were 34% and 28% of all β globins for βMD mice and 42% and 36% for βMDD mice. Hematocrit, Hb, and mean corpuscular Hb were normal for all transgenic mice, but reticulocyte levels were higher for the doubly transgenic mice versus αHβS[βMDD] mice older than 30 days (10.0% ± 1.0% v 4.3% ± 0.4%; P < .001, mean ± SE, n = 20 and n = 10, respectively) and control mice (3.9% ± 0.4%). Reticulocytosis was more severe in mice less than 30 days old (>20% for αHβSβS-Ant[βMDD] mice). The median mean corpuscular hemoglobin concentration of doubly transgenic mice was higher than that of αHβS[βMDD] mice with a variable number of very dense cells. Delay times for polymerization of Hb in red blood cells from αHβSβS-Ant[βMDD] mice were shorter than those of αHβS[βMDD] mice, and there were fewer cells with delay times greater than 100 seconds. Urine-concentrating ability in control mice under ambient conditions is 2,846 ± 294 mOsm and was reduced 30% to 1,958 ± 240 mOsm, P < 4 × 10-8 in all mice expressing both transgenes. We conclude that doubly transgenic mice have a more severe phenotype than either of the two parental lines. These mice may be suitable for validating therapeutic intervention in sickle cell disease.