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Full-Text Articles in Medicine and Health Sciences

Pum1 Mediates The Posttranscriptional Regulation Of Human Fetal Hemoglobin, Yuncheng Man, Amma Owusu-Ansah, Omar Y. Mian, Umut A. Gurkan, Anton A. Komar, Merlin Nithya Gnanapragasam Dec 2022

Pum1 Mediates The Posttranscriptional Regulation Of Human Fetal Hemoglobin, Yuncheng Man, Amma Owusu-Ansah, Omar Y. Mian, Umut A. Gurkan, Anton A. Komar, Merlin Nithya Gnanapragasam

Faculty Scholarship

The fetal-to-adult hemoglobin switching at about the time of birth involves a shift in expression from γ-globin to β-globin in erythroid cells. Effective re-expression of fetal γ-globin can ameliorate sickle cell anemia and β-thalassemia. Despite the physiological and clinical relevance of this switch, its posttranscriptional regulation is poorly understood. Here, we identify Pumilo 1 (PUM1), an RNA-binding protein with no previously reported functions in erythropoiesis, as a direct posttranscriptional regulator of β-globin switching. PUM1, whose expression is regulated by the erythroid master transcription factor erythroid Krüppel-like factor (EKLF/KLF1), peaks during erythroid differentiation, binds γ-globin messenger RNA (mRNA), and reduces γ-globin …


Multispectral Imaging For Microchip Electrophoresis Enables Point-Of-Care Newborn Hemoglobin Variant Screening, Ran An, Yuning Huang, Anne Rocheleau, Qiaochu Zhang, Yuncheng Man, Zoe Sekyonda, Amma Owusu-Ansah, Umut A. Gurkan Dec 2022

Multispectral Imaging For Microchip Electrophoresis Enables Point-Of-Care Newborn Hemoglobin Variant Screening, Ran An, Yuning Huang, Anne Rocheleau, Qiaochu Zhang, Yuncheng Man, Zoe Sekyonda, Amma Owusu-Ansah, Umut A. Gurkan

Faculty Scholarship

Hemoglobin (Hb) disorders affect nearly 7% of the world's population. Globally, around 400,000 babies are born annually with sickle cell disease (SCD), primarily in sub-Saharan Africa where morbidity and mortality rates are high. Screening, early diagnosis, and monitoring are not widely accessible due to technical challenges and cost. We hypothesized that multispectral imaging will allow sensitive hemoglobin variant identification in existing affordable paper-based Hb electrophoresis. To test this hypothesis, we developed the first integrated point-of-care multispectral Hb variant test: Gazelle-Multispectral. Here, we evaluated the accuracy of Gazelle-Multispectral for Hb variant newborn screening in 265 newborns with known hemoglobin variants including …


Catch Bonds In Sickle Cell Disease: Shear-Enhanced Adhesion Of Red Blood Cells To Laminin, Utku Goreke, Shamreen Iram, Gundeep Singh, Sergio Domínguez-Medina, Yuncheng Man, Allison Bode, Ran An, Jane A. Little, Christopher L. Wirth, Michael Hinczewski, Umut A. Gurkan Nov 2022

Catch Bonds In Sickle Cell Disease: Shear-Enhanced Adhesion Of Red Blood Cells To Laminin, Utku Goreke, Shamreen Iram, Gundeep Singh, Sergio Domínguez-Medina, Yuncheng Man, Allison Bode, Ran An, Jane A. Little, Christopher L. Wirth, Michael Hinczewski, Umut A. Gurkan

Faculty Scholarship

Could the phenomenon of catch bonding—force-strengthened cellular adhesion—play a role in sickle cell disease, where abnormal red blood cell (RBC) adhesion obstructs blood flow? Here we investigate the dynamics of sickle RBCs adhering to a surface functionalized with the protein laminin (a component of the extracellular matrix around blood vessels) under physiologically relevant micro-scale flow. First, using total internal reflectance microscopy we characterize the spatial fluctuations of the RBC membrane above the laminin surface before detachment. The complex dynamics we observe suggest the possibility of catch bonding, where the mean detachment time of the cell from the surface initially increases …


Chronic Red Cell Exchange In Sickle Cell Patients With Iron Overload May Not Affect Mortality, Yi Yuan Zhou, Hollie M. Reeves, Robert W. Maitta Sep 2022

Chronic Red Cell Exchange In Sickle Cell Patients With Iron Overload May Not Affect Mortality, Yi Yuan Zhou, Hollie M. Reeves, Robert W. Maitta

Faculty Scholarship

Sickle cell disease (SCD) is an inherited blood disorder that affects ~100,000 Americans (1, 2). In SCD, red blood cells (RBC) containing aberrant sickle hemoglobin (HgbS) become sickle-shaped at low oxygen tension and stick together leading to obstructed blood flow. The resulting decrease in tissue oxygenation causes chronic complications such as vasculo-occlusive pain crises among others that require frequent hospitalizations (3). Chronic RBC transfusions play a prominent role in the treatment of this disease by improving oxygenation through addition of normal RBC and dilution of RBC containing HgbS (4, 5). However, the major disadvantage of management with simple transfusion is …


Occlusionchip: A Functional Microcapillary Occlusion Assay Complementary To Ektacytometry For Detection Of Small-Fraction Red Blood Cells With Abnormal Deformability, Yuncheng Man, Ran An, Karamoja Monchamp, Zoe Sekyonda, Erdem Kucukal, Chiara Federici, William J. Wulftange, Utku Goreke, Allison Bode, Umut A. Gurkan Aug 2022

Occlusionchip: A Functional Microcapillary Occlusion Assay Complementary To Ektacytometry For Detection Of Small-Fraction Red Blood Cells With Abnormal Deformability, Yuncheng Man, Ran An, Karamoja Monchamp, Zoe Sekyonda, Erdem Kucukal, Chiara Federici, William J. Wulftange, Utku Goreke, Allison Bode, Umut A. Gurkan

Faculty Scholarship

Red blood cell (RBC) deformability is a valuable hemorheological biomarker that can be used to assess the clinical status and response to therapy of individuals with sickle cell disease (SCD). RBC deformability has been measured by ektacytometry for decades, which uses shear or osmolar stress. However, ektacytometry is a population based measurement that does not detect small-fractions of abnormal RBCs. A single cell-based, functional RBC deformability assay would complement ektacytometry and provide additional information. Here, we tested the relative merits of the OcclusionChip, which measures RBC deformability by microcapillary occlusion, and ektacytometry. We tested samples containing glutaraldehyde-stiffened RBCs for up …


Antithrombin-Iii Mitigates Thrombin-Mediated Endothelial Cell Contraction And Sickle Red Blood Cell Adhesion In Microscale Flow, William J. Wulftange, Erdem Kucukal, Yuncheng Man, Ran An, Karamoja Monchamp, Charlotte D. Sevrain, Himanshu R. Dashora, Allison Bode, Jane A. Little, Umut A. Gurkan Jul 2022

Antithrombin-Iii Mitigates Thrombin-Mediated Endothelial Cell Contraction And Sickle Red Blood Cell Adhesion In Microscale Flow, William J. Wulftange, Erdem Kucukal, Yuncheng Man, Ran An, Karamoja Monchamp, Charlotte D. Sevrain, Himanshu R. Dashora, Allison Bode, Jane A. Little, Umut A. Gurkan

Faculty Scholarship

Individuals with sickle cell disease (SCD) have persistently elevated thrombin generation that results in a state of systemic hypercoagulability. Antithrombin-III (ATIII), an endogenous serine protease inhibitor, inhibits several enzymes in the coagulation cascade, including thrombin. Here, we utilize a biomimetic microfluidic device to model the morphology and adhesive properties of endothelial cells (ECs) activated by thrombin and examine the efficacy of ATIII in mitigating the adhesion of SCD patient-derived red blood cells (RBCs) and EC retraction. Microfluidic devices were fabricated, seeded with ECs, and incubated under physiological shear stress. Cells were then activated with thrombin with or without an ATIII …


Anti‐Cd20 Therapeutic Options In Immune‐Mediated Thrombotic Thrombocytopenic Purpura, Robert W. Maitta Apr 2022

Anti‐Cd20 Therapeutic Options In Immune‐Mediated Thrombotic Thrombocytopenic Purpura, Robert W. Maitta

Faculty Scholarship

Immunosuppression with rituximab in immune-mediated thrombotic thrombocytopenic purpura helps decrease production of autoantibody mediating ADAMTS13 clearance from circulation. Failure to respond to rituximab in a satisfactory way or made difficult by adverse events to the medication does not represent a reason to stop considering anti-CD20 therapies to control antibody production. Therefore, both of atumumab and obinutuzumab with specificity to CD20, represent potentially valuable therapeutic tools in patients who are not candidates for rituximab. Commentary on: Doyle et al. The use of obinutuzumab and ofatumumab in the treatment of immune thrombotic thrombocytopenic purpura. Br J Haematol. 2022;198:391-396.1.