Browsing by Author "Yao, Jun"

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    Differential responses to lithium in hyperexcitable neurons from patients with bipolar disorder.
    (NPG, 2015-11-05) Mertens, Jerome; Wang, Qiu-Wen; Kim, Yongsung; Yu, Diana X.; Pham, Son; Yang, Bo; Zheng, Yi; Diffenderfer, Kenneth E.; Zhang, Jian; Soltani, Sheila; Eames, Tameji; Schafer, Simon T.; Boyer, Leah; Marchetto, Maria C.; Nurnberger, John I.; Calabrese, Joseph R.; Oedegaard, Ketil J.; McCarthy, Michael J.; Zandi, Peter P.; Alda, Martin; Nievergelt, Caroline M.; Mi, Shuangli; Brennand, Kristen J.; Kelsoe, John R.; Gage, Fred H.; Yao, Jun; Department of Psychiatry, IU School of Medicine
    Bipolar disorder is a complex neuropsychiatric disorder that is characterized by intermittent episodes of mania and depression; without treatment, 15% of patients commit suicide. Hence, it has been ranked by the World Health Organization as a top disorder of morbidity and lost productivity. Previous neuropathological studies have revealed a series of alterations in the brains of patients with bipolar disorder or animal models, such as reduced glial cell number in the prefrontal cortex of patients, upregulated activities of the protein kinase A and C pathways and changes in neurotransmission. However, the roles and causation of these changes in bipolar disorder have been too complex to exactly determine the pathology of the disease. Furthermore, although some patients show remarkable improvement with lithium treatment for yet unknown reasons, others are refractory to lithium treatment. Therefore, developing an accurate and powerful biological model for bipolar disorder has been a challenge. The introduction of induced pluripotent stem-cell (iPSC) technology has provided a new approach. Here we have developed an iPSC model for human bipolar disorder and investigated the cellular phenotypes of hippocampal dentate gyrus-like neurons derived from iPSCs of patients with bipolar disorder. Guided by RNA sequencing expression profiling, we have detected mitochondrial abnormalities in young neurons from patients with bipolar disorder by using mitochondrial assays; in addition, using both patch-clamp recording and somatic Ca2+ imaging, we have observed hyperactive action-potential firing. This hyperexcitability phenotype of young neurons in bipolar disorder was selectively reversed by lithium treatment only in neurons derived from patients who also responded to lithium treatment. Therefore, hyperexcitability is one early endophenotype of bipolar disorder, and our model of iPSCs in this disease might be useful in developing new therapies and drugs aimed at its clinical treatment.
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    Effects of donor-specific microvascular anatomy on hemodynamic perfusion in human choriocapillaris
    (Springer Nature, 2023-12-19) An, Senyou; Yu, Huidan; Islam, MD Mahfuzul; Zhang, Xiaoyu; Zhan, Yuting; Olivieri, Joseph J.; Ambati, Jayakrishna; Yao, Jun; Gelfand, Bradley D.; Mechanical and Energy Engineering, Purdue School of Engineering and Technology
    Evidence from histopathology and clinical imaging suggest that choroidal anatomy and hemodynamic perfusion are among the earliest changes in retinal diseases such as age-related macular degeneration (AMD). However, how inner choroidal anatomy affects hemodynamic perfusion is not well understood. Therefore, we sought to understand the influences of choroidal microvascular architecture on the spatial distribution of hemodynamic parameters in choriocapillaris from human donor eyes using image-based computational hemodynamic (ICH) simulations. We subjected image-based inner choroid reconstructions from eight human donor eyes to ICH simulation using a kinetic-based volumetric lattice Boltzmann method to compute hemodynamic distributions of velocity, pressure, and endothelial shear stress. Here, we demonstrate that anatomic parameters, including arteriolar and venular arrangements and intercapillary pillar density and distribution exert profound influences on inner choroidal hemodynamic characteristics. Reductions in capillary, arteriolar, and venular density not only reduce the overall blood velocity within choriocapillaris, but also substantially increase its spatial heterogeneity. These first-ever findings improve understanding of how choroidal anatomy affects hemodynamics and may contribute to pathogenesis of retinal diseases such as AMD.