Browsing by Author "Hu, Ping"

Now showing 1 - 6 of 6
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    Adeno-Associated Virus Overexpression of Angiotensin-Converting Enzyme-2 Reverses Diabetic Retinopathy in Type 1 Diabetes in Mice
    (Elsevier, 2016) Dominguez, James M., II; Hu, Ping; Caballero, Sergio; Moldovan, Leni; Verma, Amrisha; Oudit, Gavin Y.; Li, Qiuhong; Grant, Maria B.; Department of Ophthalmology, School of Medicine
    Angiotensin-converting enzyme (ACE)-2 is the primary enzyme of the vasoprotective axis of the renin angiotensin system that regulates the classic renin angiotensin system axis. We aimed to determine whether local retinal overexpression of adenoassociated virus (AAV)-ACE2 prevents or reverses diabetic retinopathy. Green fluorescent protein (GFP)-chimeric mice were generated to distinguish resident (retinal) from infiltrating bone marrow-derived inflammatory cells and were made diabetic using streptozotocin injections. Retinal digestion using trypsin was performed and acellular capillaries enumerated. Capillary occlusion by GFP(+) cells was used to measure leukostasis. Overexpression of ACE2 prevented (prevention cohort: untreated diabetic, 11.3 ± 1.4; ACE2 diabetic, 6.4 ± 0.9 per mm(2)) and partially reversed (reversal cohort: untreated diabetic, 15.7 ± 1.9; ACE2 diabetic, 6.5 ± 1.2 per mm(2)) the diabetes-associated increase of acellular capillaries and the increase of infiltrating inflammatory cells into the retina (F4/80(+)) (prevention cohort: untreated diabetic, 24.2 ± 6.7; ACE2 diabetic, 2.5 ± 1.6 per mm(2); reversal cohort: untreated diabetic, 56.8 ± 5.2; ACE2 diabetic, 5.6 ± 2.3 per mm(2)). In both study cohorts, intracapillary bone marrow-derived cells, indicative of leukostasis, were only observed in diabetic animals receiving control AAV injections. These results indicate that diabetic retinopathy, and possibly other diabetic microvascular complications, can be prevented and reversed by locally restoring the balance between the classic and vasoprotective renin angiotensin system.
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    CX3CR1 deficiency accelerates the development of retinopathy in a rodent model of type 1 diabetes
    (Springer, 2016-11) Beli, Eleni; Dominguez, James M.; Hu, Ping; Thinschmidt, Jeffrey S.; Caballero, Sergio; Calzi, Sergio Li; Luo, Defang; Shanmugam, Sumathi; Salazar, Tatiana; Duan, Yaqian; Boulton, Michael E.; Mohr, Susanna; Abcouwer, Steven F.; Saban, Daniel R.; Harrison, Jeffrey K.; Grant, Maria B.; Ophthalmology, School of Medicine
    In this study, the role of CX3CR1 in the progression of diabetic retinopathy (DR) was investigated. The retinas of wild type (WT), CX3CR1 null (CX3CR1gfp/gfp, KO) and heterozygous (CX3CR1+/gfp, Het) mice were compared in the presence and absence of streptozotocin (STZ) induced diabetes. CX3CR1 deficiency in STZ-KO increased vascular pathology at 4 months of diabetes, as a significant increase in acellular capillaries was observed only in the STZ-KO group. CX3CR1 deficiency and diabetes had similar effects on retinal neurodegeneration measured by an increase in DNA fragmentation. Retinal vascular pathology in STZ-KO mice was associated with increased numbers of monocyte-derived macrophages in the retina. Furthermore, compared to STZ-WT, STZ-KO mice exhibited increased numbers of inflammatory monocytes in the bone marrow and impaired homing of monocytes to the spleen. Induction of retinal IL-10 expression by diabetes was significantly less in KO mice, and when bone marrow-derived macrophages from KO mice were maintained in high glucose they expressed significantly less IL-10 and more TNF-α in response to LPS stimulation. These findings support that CX3CR1 deficiency accelerates the development of vascular pathology in DR through increased recruitment of proinflammatory myeloid cells that demonstrate reduced expression of anti-inflammatory IL-10.
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    Hematopoietic stem/progenitor involvement in retinal microvascular repair during diabetes: Implications for bone marrow rejuvenation
    (Elsevier, 2017-10) Bhatwadekar, Ashay D.; Duan, Yaqian; Korah, Maria; Thinschmidt, Jeffrey S.; Hu, Ping; Leley, Sameer P.; Caballero, Sergio; Shaw, Lynn; Busik, Julia; Grant, Maria B.; Ophthalmology, School of Medicine
    The widespread nature of diabetes affects all organ systems of an individual including the bone marrow. Long-term damage to the cellular and extracellular components of the bone marrow leads to a rapid decline in the bone marrow-hematopoietic stem/progenitor cells (HS/PCs) compartment. This review will highlight the importance of bone marrow microenvironment in maintaining bone marrow HS/PC populations and the contribution of these key populations in microvascular repair during the natural history of diabetes. The autonomic nervous system can initiate and propagate bone marrow dysfunction in diabetes. Systemic pharmacological strategies designed to protect the bone marrow-HS/PC population from diabetes induced-oxidative stress and advanced glycation end product accumulation represent a new approach to target diabetic retinopathy progression. Protecting HS/PCs ensures their participation in vascular repair and reduces the risk of vasogdegeneration occurring in the retina.
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    Loss of survival factors and activation of inflammatory cascades in brain sympathetic centers in type 1 diabetic mice
    (American Physiological Society, 2015-04-15) Hu, Ping; Thinschmidt, Jeffrey S.; Caballero, Sergio; Adamson, Samuel; Cole, Louise; Chan-Ling, Tailoi; Grant, Maria B.; Department of Ophthalmology, IU School of Medicine
    Neuroinflammation and neurodegeneration have been observed in the brain in type 1 diabetes (T1D). However, little is known about the mediators of these effects. In T1D mice with 12- and 35-wk duration of diabetes we examined two mechanisms of neurodegeneration, loss of the neuroprotective factors insulin-like growth factor I (IGF-I) and IGF-binding protein-3 (IGFBP-3) and changes in indoleamine 2,3-dioxygenase (IDO) expression in the brain, and compared the response to age-matched controls. Furthermore, levels of matrix metalloproteinase-2 (MMP-2), nucleoside triphosphate diphosphohydrolase-1 (CD39), and ionized calcium-binding adaptor molecule 1 (Iba-1) were utilized to assess inflammatory changes in astrocytes, microglia, and blood vessels. In the diabetic hypothalamus (HYPO), we observed 20% reduction in neuronal soma diameter (P<0.05) and reduced neuronal expression of IGFBP-3 (-32%, P<0.05) and IGF-I (-15%, P<0.05) compared with controls at 35 wk. In diabetic HYPO, MMP-2 expression was increased in astrocytes (46%, P<0.01), and IDO⁺ cell density rose by (62%, P<0.05). CD39 expression dropped by 30% (P<0.05) in microglia and blood vessels. With 10 wk of systemic treatment using minocycline, an anti-inflammatory agent that crosses the blood-brain barrier, MMP-2, IDO, and CD39 levels normalized (P<0.05). Our results suggest that increased IDO and early loss of CD39⁺ protective cells lead to activation of inflammation in sympathetic centers of the CNS. As a downstream effect, the loss of the neuronal survival factors IGFBP-3 and IGF-I and the neurotoxic products of the kynurenine pathway contribute to the loss of neuronal density observed in the HYPO in T1D.
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    P38α/JNK signaling restrains erythropoiesis by suppressing Ezh2-mediated epigenetic silencing of Bim
    (Springer Nature, 2018-08-29) Hu, Ping; Nebreda, Angel R.; Hanenberg, Helmut; Kinnebrew, Garrett H.; Ivan, Mircea; Yoder, Mervin C.; Filippi, Marie-Dominique; Broxmeyer, Hal E.; Kapur, Reuben; Pediatrics, School of Medicine
    While erythropoietin (EPO) constitutes the major treatment for anemia, a range of anemic disorders remain resistant to EPO treatment. The need for alternative therapeutic strategies requires the identification of mechanisms that physiologically restrain erythropoiesis. Here we show that P38α restrains erythropoiesis in mouse and human erythroblasts independently of EPO by integrating apoptotic signals during recovery from anemia. P38α deficiency promotes JNK activation through increased expression of Map3k4 via a negative feedback mechanism. JNK prevents Cdk1-mediated phosphorylation and subsequent degradation by Smurf2 of the epigenetic silencer Ezh2. Stabilized Ezh2 silences Bim expression and protects erythroblasts from apoptosis. Thus, we identify P38α/JNK signaling as a molecular brake modulating erythropoiesis through epigenetic silencing of Bim. We propose that inhibition of P38α, by enhancing erythropoiesis in an EPO-independent fashion, may provide an alternative strategy for the treatment of anemia.
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    Specific mesoderm subset derived from human pluripotent stem cells ameliorates microvascular pathology in type 2 diabetic mice
    (American Association for the Advancement of Science, 2022) Gil, Chang-Hyun; Chakraborty, Dibyendu; Vieira, Cristiano P.; Prasain, Nutan; Calzi, Sergio Li; Fortmann, Seth D.; Hu, Ping; Banno, Kimihiko; Jamal, Mohamed; Huang, Chao; Sielski, Micheli S.; Lin, Yang; Huang, Xinxin; Dupont, Mariana D.; Floyd, Jason L.; Prasad, Ram; Longhini, Ana Leda F.; McGill, Trevor J.; Chung, Hyung-Min; Murphy, Michael P.; Kotton, Darrell N.; Boulton, Michael E.; Yoder, Mervin C.; Grant, Maria B.; Pediatrics, School of Medicine
    Human induced pluripotent stem cells (hiPSCs) were differentiated into a specific mesoderm subset characterized by KDR+CD56+APLNR+ (KNA+) expression. KNA+ cells had high clonal proliferative potential and specification into endothelial colony-forming cell (ECFCs) phenotype. KNA+ cells differentiated into perfused blood vessels when implanted subcutaneously into the flank of nonobese diabetic/severe combined immunodeficient mice and when injected into the vitreous of type 2 diabetic mice (db/db mice). Transcriptomic analysis showed that differentiation of hiPSCs derived from diabetics into KNA+ cells was sufficient to change baseline differences in gene expression caused by the diabetic status and reprogram diabetic cells to a pattern similar to KNA+ cells derived from nondiabetic hiPSCs. Proteomic array studies performed on retinas of db/db mice injected with either control or diabetic donor-derived KNA+ cells showed correction of aberrant signaling in db/db retinas toward normal healthy retina. These data provide "proof of principle" that KNA+ cells restore perfusion and correct vascular dysfunction in db/db mice.