Browsing by Author "Liu, Liqiong"

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    Further Characterization of Multi-Organ DEARE and Protection by 16,16 Dimethyl Prostaglandin E2 in a Mouse Model of the Hematopoietic Acute Radiation Syndrome
    (BioOne, 2023) Wu, Tong; Pelus, Louis M.; Plett, P. Artur; Sampson, Carol H.; Chua, Hui Lin; Fisher, Alexa; Feng, Hailin; Liu, Liqiong; Li, Hongge; Ortiz, Miguel; Chittajallu, Supriya; Luo, Qianyi; Bhatwadekar, Ashay D.; Meyer, Timothy B.; Zhang, Xin; Zhou, Daohong; Fischer, Kathryn D.; McKinzie, David L.; Miller, Steven J.; Orschell, Christie M.; Medicine, School of Medicine
    Survivors of acute radiation exposure suffer from the delayed effects of acute radiation exposure (DEARE), a chronic condition affecting multiple organs, including lung, kidney, heart, gastrointestinal tract, eyes, and brain, and often causing cancer. While effective medical countermeasures (MCM) for the hematopoietic-acute radiation syndrome (H-ARS) have been identified and approved by the FDA, development of MCM for DEARE has not yet been successful. We previously documented residual bone marrow damage (RBMD) and progressive renal and cardiovascular DEARE in murine survivors of H-ARS, and significant survival efficacy of 16,16-dimethyl prostaglandin E2 (dmPGE2) given as a radioprotectant or radiomitigator for H-ARS. We now describe additional DEARE (physiological and neural function, progressive fur graying, ocular inflammation, and malignancy) developing after sub-threshold doses in our H-ARS model, and detailed analysis of the effects of dmPGE2 administered before (PGE-pre) or after (PGE-post) lethal total-body irradiation (TBI) on these DEARE. Administration of PGE-pre normalized the twofold reduction of white blood cells (WBC) and lymphocytes seen in vehicle-treated survivors (Veh), and increased the number of bone marrow (BM) cells, splenocytes, thymocytes, and phenotypically defined hematopoietic progenitor cells (HPC) and hematopoietic stem cells (HSC) to levels equivalent to those in non-irradiated age-matched controls. PGE-pre significantly protected HPC colony formation ex vivo by >twofold, long term-HSC in vivo engraftment potential up to ninefold, and significantly blunted TBI-induced myeloid skewing. Secondary transplantation documented continued production of LT-HSC with normal lineage differentiation. PGE-pre reduced development of DEARE cardiovascular pathologies and renal damage; prevented coronary artery rarefication, blunted progressive loss of coronary artery endothelia, reduced inflammation and coronary early senescence, and blunted radiation-induced increase in blood urea nitrogen (BUN). Ocular monocytes were significantly lower in PGE-pre mice, as was TBI-induced fur graying. Increased body weight and decreased frailty in male mice, and reduced incidence of thymic lymphoma were documented in PGE-pre mice. In assays measuring behavioral and cognitive functions, PGE-pre reduced anxiety in females, significantly blunted shock flinch response, and increased exploratory behavior in males. No effect of TBI was observed on memory in any group. PGE-post, despite significantly increasing 30-day survival in H-ARS and WBC and hematopoietic recovery, was not effective in reducing TBI-induced RBMD or any other DEARE. In summary, dmPGE2 administered as an H-ARS MCM before lethal TBI significantly increased 30-day survival and ameliorated RBMD and multi-organ and cognitive/behavioral DEARE to at least 12 months after TBI, whereas given after TBI, dmPGE2 enhances survival from H-ARS but has little impact on RBMD or other DEARE.
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    Rapid Mobilization Reveals a Highly Engraftable Hematopoietic Stem Cell
    (Elsevier, 2018-01-11) Hoggatt, Jonathan; Singh, Pratibha; Tate, Tiffany A.; Chou, Bin-Kuan; Datari, Shruti R.; Fukuda, Seiji; Liu, Liqiong; Kharchenko, Peter V.; Schajnovitz, Amir; Baryawno, Ninib; Mercier, Francois E.; Boyer, Joseph; Gardner, Jason; Morrow, Dwight M.; Scadden, David T.; Pelus, Louis M.; Microbiology and Immunology, School of Medicine
    Hematopoietic stem cell transplantation is a potential curative therapy for malignant and nonmalignant diseases. Improving the efficiency of stem cell collection and the quality of the cells acquired can broaden the donor pool and improve patient outcomes. We developed a rapid stem cell mobilization regimen utilizing a unique CXCR2 agonist, GROβ, and the CXCR4 antagonist AMD3100. A single injection of both agents resulted in stem cell mobilization peaking within 15 min that was equivalent in magnitude to a standard multi-day regimen of granulocyte colony-stimulating factor (G-CSF). Mechanistic studies determined that rapid mobilization results from synergistic signaling on neutrophils, resulting in enhanced MMP-9 release, and unexpectedly revealed genetic polymorphisms in MMP-9 that alter activity. This mobilization regimen results in preferential trafficking of stem cells that demonstrate a higher engraftment efficiency than those mobilized by G-CSF. Our studies suggest a potential new strategy for the rapid collection of an improved hematopoietic graft.
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    A Single Radioprotective Dose of Prostaglandin E2 Blocks Irradiation-Induced Apoptotic Signaling and Early Cycling of Hematopoietic Stem Cells
    (Elsevier, 2020-07-30) Patterson, Andrea M.; Liu, Liqiong; Sampson, Carol H.; Plett, P. Artur; Li, Hongge; Singh, Pratibha; Mohammad, Khalid S.; Hoggatt, Jonathan; Capitano, Maegan L.; Orschell, Christie M.; Pelus, Louis M.; Medicine, School of Medicine
    Ionizing radiation exposure results in acute and delayed bone marrow suppression. Treatment of mice with 16,16-dimethyl prostaglandin E2 (dmPGE2) prior to lethal ionizing radiation (IR) facilitates survival, but the cellular and molecular mechanisms are unclear. In this study we show that dmPGE2 attenuates loss and enhances recovery of bone marrow cellularity, corresponding to a less severe hematopoietic stem cell nadir, and significantly preserves long-term repopulation capacity and progenitor cell function. Mechanistically, dmPGE2 suppressed hematopoietic stem cell (HSC) proliferation through 24 h post IR, which correlated with fewer DNA double-strand breaks and attenuation of apoptosis, mitochondrial compromise, oxidative stress, and senescence. RNA sequencing of HSCs at 1 h and 24 h post IR identified a predominant interference with IR-induced p53-downstream gene expression at 1 h, and confirmed the suppression of IR-induced cell-cycle genes at 24 h. These data identify mechanisms of dmPGE2 radioprotection and its potential role as a medical countermeasure against radiation exposure.
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    Survivin is Required for Mouse and Human Bone Marrow Mesenchymal Stromal Cell Function
    (Wiley, 2017) Singh, Pratibha; Fukuda, Seiji; Liu, Liqiong; Chitteti, Brahmananda Reddy; Pelus, Louis M.; Microbiology and Immunology, School of Medicine
    Although mesenchymal stromal cells (MSCs) have significant potential in cell-based therapies, little is known about the factors that regulate their functions. While exploring regulatory molecules potentially involved in MSC activities, we found that the endogenous multifunctional factor Survivin is essential for MSC survival, expansion, lineage commitment, and migration. Pharmacological or genetic blockade of Survivin expression in mouse and human bone marrow MSC enhances caspase 3 and 7 expression and reduces proliferation resulting in fewer MSC and clonogenic colony-forming unit-fibroblasts (CFU-F), whereas ectopic Survivin overexpression in MSC results in their expansion. Survivin is also required for the MSC proliferative responses to basic fibroblast growth factor and platelet derived growth factor. In a wound healing model, Survivin inhibition results in suppression of MSC migration to the wound site. In addition, loss of Survivin in MSCs compromises their hematopoiesis-supporting capacity. These results demonstrate that Survivin is a key regulator of mouse and human MSC function, and suggest that targeted modulation of Survivin in MSCs may have clinical utility to enhance MSC recovery and activity following insult or stress.