Wanxing Cui - Academia.edu (original) (raw)

Papers by Wanxing Cui

ACS Biomaterials Science & Engineering, Jul 28, 2017

The major concern of pancreatic islet transplantation is that the implanted islets are exposed to... more The major concern of pancreatic islet transplantation is that the implanted islets are exposed to the immune system of the recipient. To overcome this challenge, the peptide amphiphile (PA) nanomatrix gel was used for immunoisolation of islets through microencapsulation. The PA can self-assemble to form a nanomatrix gel with an extracellular matrix-mimicking, islet nurturing microenvironment and a semipermeable immune barrier. In this study, the islet protective effect of the PA nanomatrix gel was evaluated by coculture of PA-encapsulated human islets with differentiated U937 cells (human monocyte cell-line) for 3 and 7 days. The coculture of the bare islets with the differentiated U937 cells stimulated proinflammatory cytokine (IL-1β and TNF-α) secretion and caused islet death after 7 days, which simulated an early inflammatory response environment after islet transplantation. The PA-encapsulated islets, however, did not stimulate proinflammatory cytokine secretion and maintained islet viability up to 7 days. More insulinproducing β cells were observed when islets were PA-encapsulated than control islets with the differentiated U937 cells for 7 days compared to the bare islets. This result was also confirmed by dithizone staining analysis. Further evaluation of islet functionality was assessed by a glucosestimulated insulin secretion test. The PA-encapsulated islets showed greater insulin secretion *

International Journal of Nanomedicine

Coating of nanomedicine with cell membranes has attracted increasing attention as it can boost bi... more Coating of nanomedicine with cell membranes has attracted increasing attention as it can boost biocompatibility and improve the efficiency of treatment. Herein, we prepared innovative tumor cell-membrane-coated vesicles based on photodynamic therapy (PDT) drug indocyanine green (ICG) and explore the effect on melanoma in vitro and in vivo. Methods: ICG was coated with B16 cell membranes (I@BM NVs) by sonication and extrusion, and the morphological characteristics of I@BM NVs were evaluated by transmission electron microscopy (TEM) and NP-tracking analysis. Homologous cellular uptake was evaluated by flow cytometry (FCM) after staining by DiD dye. Cellular cytotoxicity was evaluated by cell counting kit-8 assay and the anti-tumor effect in vitro was assessed by FCM and western blotting. The anti-tumor effect in vivo was evaluated in a B16 xenograft model in mice. The tumor micro-environment was investigated by FCM and real-time PCR. Results: The vesicles are stable and uniform in nature, and show strong homologous targeting in vivo and in vitro. The vesicles can generate reactive oxygen species to induce apoptosis of B16 cells under near-infrared irradiation. Furthermore, the I@BM NVs induce a significant anti-tumor response in vivo, and perform better with respect to both tumor growth inhibition and lifespan extension. Analysis of immunocytes in the tumor microenvironment showed significant reductions in numbers of myeloid-derived suppressor cells and tumor-associated M2 macrophages in mice in the I@BM NVs group. This was accompanied by significant increases in numbers of M1 macrophages and proliferative CD4 + /CD8 + T cells. Expression levels of IFN-γ and IL-2 increased in the I@BM NVs group, while expression of TGF-β and IL-10 decreased. Conclusion: The results show that the I@BM NVs are feasible drugs for the treatment of melanoma by inducing cell apoptosis under NIR and shifting the immunosuppressive tumor microenvironment in vivo.

Cell Cycle

The successful translation of mesenchymal stem cells (MSCs) from bench to bedside is predicated u... more The successful translation of mesenchymal stem cells (MSCs) from bench to bedside is predicated upon their regenerative capabilities and immunomodulatory potential. Many challenges still exist in making MSCs a viable and cost-effective therapeutic option, due in part to the challenges of sourcing MSCs from adult tissues and inconsistencies in the characterization of MSCs. In many cases, adult MSC collection is an invasive procedure, and ethical concerns and age-related heterogeneity further complicate obtaining adult tissue derived MSCs at the scales needed for clinical applications. Alternative adult sources, such as post-partum associated tissues, offer distinct advantages to overcome these challenges. However, successful therapeutic applications rely on the efficient ex-vivo expansion of the stem cells while avoiding any culture-related phenotypic alterations, which requires optimized and standardized isolation, culture, and cell preservation methods. In this review, we have compared the isolation and culture methods for MSCs originating from the human amniotic membrane (hAMSCs) of the placenta to identify the elements that support the extended subculture potential of hAMSCs without compromising their immune-privileged, pluripotent regenerative potential.Abbreviations:AM: Human amniotic membrane; ASCs: Adipose tissue-derived stem cells; BM-MSCs: Bone marrow-mesenchymal stem cells; DMEM: Dulbecco's modified eagle medium; DT: Doubling time; EMEM: Eagle's modified essential medium; ESCM: Embryonic stem cell markers; ESCs: Embryonic stem cells; hAECs: Human amniotic epithelial cells; hAMSCs: Human amniotic mesenchymal stem cells; HLA: Human leukocyte antigen; HM: Hematopoietic markers; IM: Immunogenicity markers; MHC: Major histocompatibility complex; MSCs: Mesenchymal stem cells; MCSM: Mesenchymal cell surface markers; Nanog: NANOG homeobox; Oct: Octamer binding transcription factor 4; P: Passage; PM: Pluripotency markers; STRO-1: Stromal precursor antigen-1; SCP: Subculture potential; Sox-2: Sry-related HMG box gene 2; SSEA-4: Stage-specific embryonic antigen; TRA: Tumor rejection antigen.

Mesenchymal stem cells are a potential therapeutic candidate for cerebral infarction due to their... more Mesenchymal stem cells are a potential therapeutic candidate for cerebral infarction due to their anti-inflammatory proprieties. However, ensuring the engraftment of sufficient cells into the affected brain area remains a challenge. Herein, magnetic targeting techniques were used for the noninvasive transplantation of a large number of cells noninvasively. Mice subjected to permanent middle cerebral artery occlusion surgery were administered mesenchymal stem cells labeled or not with iron oxide@polydopamine nanoparticles by tail vein injection. Iron oxide@polydopamine particles were characterized by transmission electron microscopy, and labeled mesenchymal stem cells were characterized by flow cytometry and their differentiation potential was assessed in vitro . Following the systemic injection of iron oxide@polydopamine-labeled mesenchymal stem cells into permanent transient middle cerebral artery occlusion-induced mice, magnetic navigation increased the MSCs localization to the br...

Journal of Visualized Experiments

Although the liver is currently accepted as the primary transplantation site for human islets in ... more Although the liver is currently accepted as the primary transplantation site for human islets in clinical settings, islets are transplanted under the kidney capsule in most rodent preclinical islet transplantation studies. This model is commonly used because murine intrahepatic islet transplantation is technically challenging, and a high percentage of mice could die from surgical complications, especially bleeding from the injection site post-transplantation. In this study, two procedures that can minimize the incidence of post-infusion portal vein bleeding are demonstrated. The first method applies an absorbable hemostatic gelatin sponge to the injection site, and the second method involves penetrating the islet injection needle through the fat tissue first and then into the portal vein by using the fat tissue as a physical barrier to stop bleeding. Both methods could effectively prevent bleeding-induced mouse death. The whole liver section showing islet distribution and evidence of islet thrombosis post-transplantation, a typical feature for intrahepatic islet transplantation, were presented. These improved protocols refine the intrahepatic islet transplantation procedures and may help laboratories set up the procedure to study islet survival and function in pre-clinical settings.

Journal of Visualized Experiments, 2021

American Journal of Transplantation, 2020

Alpha‐1 antitrypsin (AAT) has protective functions in animal islet transplantation models. While ... more Alpha‐1 antitrypsin (AAT) has protective functions in animal islet transplantation models. While the therapeutic effect of AAT therapy is currently being tested in clinical trials, we investigated the mechanism of AAT protection in a clinically relevant marginal intrahepatic human islet transplantation model. In recipients receiving islets and AAT, 68.9% (20/29) reached normoglycemia, compared to 35.7% (10/28) in those receiving islets only, at 60 days posttransplant (PT). AAT‐treated mice had lower serum levels of inflammatory cytokines immediately PT. Reduced M1 macrophages were observed in livers of AAT‐treated recipients compared to controls as evidenced by flow cytometry and RNA‐seq transcriptional profiling analysis. In vitro AAT suppressed IFN‐γ‐induced M1 macrophage activation/polarization via suppression of STAT1 phosphorylation and iNOS production. AAT inhibits macrophage activation induced by cytokines or dying islets, and consequently leads to islet cell survival. In a macrophage depletion mouse model, the presence of M1 macrophages in the liver contributed to graft death. AAT, through suppressing macrophage activation, protected transplanted islets from death and dysfunction in the human islet and NOD‐SCID mouse model. The protective effect of AAT was confirmed in a major mismatch allogeneic islet transplantation model. Taken together, AAT suppresses liver macrophage activation that contributes to graft survival after transplantation.

Experimental Cell Research, 2019

A long-term hepatocyte culture maintaining liver-specific functions is very essential for both ba... more A long-term hepatocyte culture maintaining liver-specific functions is very essential for both basic research and the development of bioartificial liver devices in clinical application. However, primary hepatocytes rapidly lose their proliferation and hepatic functions over a few days in culture. This work is to establish an ornithine transcarbamylase deficiency (OTCD) patient-derived primary human hepatocyte (OTCD-PHH) culture with hepatic functions for providing an in vitro cell model. Liver tissue from an infant with OTCD was dispersed into single cells. The cells were cultured using conditional reprogramming. To characterize the cells, we assessed activities and mRNA expression of CYP3A4, 1A1, 2C9, as well as albumin and urea secretion. We found that the OTCD-PHH can be subpassaged for more than 15 passages. The cells do not express mRNA of fibroblast-specific maker, whereas they highly express markers of epithelial cells and hepatocytes. In addition, the OTCD-PHH retain native CYP3A4, 1A1, 2C9 activities and albumin secretion function at early passages. The OTCD-PHH at passages 2, 6, 9 and 13 have identical DNA fingerprint as the original tissue. Furthermore, under 3D culture environment, low urea production and hepatocyte marker staining of the OTCD-PHH were detected. The established OTCD-PHH maintain liver-specific functions at early passages and can be long-term cultured in vitro. We believe the established long-term OTCD-PHH culture is highly relevant to study liver diseases, particularly in infants with OTCD.

Experimental Biology and Medicine, 2019

Cultivation of primary human hepatocytes (PHHs) often faces obstacles including failure of long-t... more Cultivation of primary human hepatocytes (PHHs) often faces obstacles including failure of long-term in vitro culture, weak proliferation ability, rapid loss of liver-specific function and morphology, and tendency of fibrosis. Previous research focused on immortalization methods, such as telomerase and viral, to culture immortalized primary human hepatocytes, which may lose some of the normal properties. However, non-immortalized PHHs often fail to maintain long-term viability and functionality. These highlight the urgent need for developing new culture strategy for PHHs. In the present study, we isolated PHHs from fresh human liver tissues representing different liver diseases and age groups. We used conditional reprogramming, without permanent immortalization, for long-term in vitro primary human hepatocytes cultivation and characterization. For functional characterization, we assessed CYP3A4, 1A1 and 2C9 activities and measured the mRNA expression of albumin, s100a4, krt8, krt18,...

Cell Transplantation, 2001

Subcutaneous islet transplantation has become an attractive modality. With development of tissue-... more Subcutaneous islet transplantation has become an attractive modality. With development of tissue-engineering techniques, it is possible to rectify the disadvantage of poor blood supply in the subcutaneous site by reconstruction of the capillary network. According to reports, the Chitosan sponge (CS) could be used for reconstruction of in vitro capillary-like network and could be used in artificial skin equivalent. In this study, we cultured the islets in CS for future application. CSs, having 200–500 μm pore size, were prepared by freeze-drying method. Rat islets were isolated from the pancreas of Lewis rats (10 weeks old, 280–300 g, male) by collagenase digestion followed by discontinuous dextran gradient centrifugation method. Each 20 islets were seeded equally into the CSs and were cultured for 62 days with various culture media such as RPMI-1640, Dulbecco's modified Eagle's medium (DMEM), and Eagle's MEM. They contained 10% fetal bovine serum (FBS) and 5 ml/L antibio...

Stem cell research & therapy, Aug 30, 2017

Chronic pancreatitis has surgical options including total pancreatectomy to control pain. To avoi... more Chronic pancreatitis has surgical options including total pancreatectomy to control pain. To avoid surgical diabetes, the explanted pancreas can have islets harvested and transplanted. Immediately following total pancreatectomy with islet autotransplantation (TP-IAT), many islet cells die due to isolation and transplantation stresses. The percentage of patients remaining insulin free after TP-IAT is therefore low. We determined whether cotransplantation of adipose-derived mesenchymal stem cells (ASCs) from chronic pancreatitis patients (CP-ASCs) would protect islets after transplantation. In a marginal mass islet transplantation model, islets from C57BL/6 mice were cotransplanted with CP-ASCs into syngeneic streptozotocin-treated diabetic mice. Treatment response was defined by the percentage of recipients reaching normoglycemia, and by the area under the curve for glucose and c-peptide in a glucose tolerance test. Macrophage infiltration, β-cell apoptosis, and islet graft vasculatu...

Diabetes, Apr 9, 2017

Islet cell transplantation has limited effectiveness because of an instant blood-mediated inflamm... more Islet cell transplantation has limited effectiveness because of an instant blood-mediated inflammatory reaction (IBMIR) that occurs immediately after cell infusion and leads to dramatic β cell death. In intraportal islet transplantation models using mouse and human islets, we demonstrated that alpha-1 antitrypsin (AAT, Prolastin-C), a serine protease inhibitor used for the treatment of AAT deficiency, inhibits IBMIR and cytokine-induced inflammation in islets. In mice, more diabetic recipients reached normoglycemia after intraportal islet transplantation when they were treated with AAT compared to mice treated with saline. AAT suppressed blood-mediated coagulation pathways by diminishing tissue factor production, reducing plasma thrombin-antithrombin (TAT) complex levels and fibrinogen deposition on islet grafts, which correlated with less graft damage and apoptosis. AAT-treated mice showed reduced serum TNF-α levels, decreased lymphocytic infiltration, and decreased NF-κB activatio...

Molecular genetics and metabolism, Jan 24, 2015

Propionic acidemia (PA) is a disorder of intermediary metabolism with defects in the alpha or bet... more Propionic acidemia (PA) is a disorder of intermediary metabolism with defects in the alpha or beta subunits of propionyl CoA carboxylase (PCCA and PCCB respectively) enzyme. We previously described a liver culture system that uses liver-derived hemodynamic blood flow and transport parameters to restore and maintain primary human hepatocyte biology and metabolism utilizing physiologically relevant milieu concentrations. In this study, primary hepatocytes isolated from the explanted liver of an 8-year-old PA patient were cultured in the liver system for 10days and evaluated for retention of differentiated polarized morphology. The expression of PCCA and PCCB was assessed at a gene and protein level relative to healthy donor controls. Ammonia and urea levels were measured in the presence and absence of amino acid supplements to assess the metabolic consequences of branched-chain amino acid metabolism in this disease. Primary hepatocytes from the PA patient maintained a differentiated p...

Tetrahedron, 2004

We report a facile synthesis of bifunctional phospholipid conjugates by acylation of N-protected ... more We report a facile synthesis of bifunctional phospholipid conjugates by acylation of N-protected lyso-phosphatidylethanolamine with 12-acryloxy-1-dodecanoic acid and followed with deprotection and conjugation with biotin, FITC, Texas Red, or EMC groups. The lipid conjugates can be used to generate a multifunctional substrate-supported phospholipid membrane via bioconjugation reaction to biotin or covalent attachment to EMC at their hydrophilic terminus. In addition,

Tissue Engineering Part A, 2011

Pancreas, 2003

Bioartificial pancreas (BAP) transplantation offers a potential treatment of diabetes mellitus. T... more Bioartificial pancreas (BAP) transplantation offers a potential treatment of diabetes mellitus. The optimal site for BAP transplantation has not yet been established. To monitor the effect of induction of neovascularization at the intermuscular space on islet survival after allogenic transplantation of BAP. Angiogenesis was induced at the intermuscular space of diabetic Lewis rats by implanting a polyethylene terephthalate (PET) mesh bag, which enclosed a collagen sponge and biodegradable gelatin microspheres containing basic fibroblast growth factor. After confirmation of angiogenesis, BAP was prepared by mixing of 5% agarose with approximately 2,800 isolated rat (Sprague-Dawley) islets and transplanted into the prevascularized PET mesh bag. Neovascularization was observed in and around the PET mesh bag within 10 days after implantation as confirmed by macroscopic and microscopic examinations. In the presence of a collagen sponge, new blood vessels penetrated into the PET mesh bag and formed a vascular bed. After transplantation, normoglycemia was achieved in the rats within 3 days and maintained for &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;35 days. The rats gradually gained body weight, and the results of intravenous glucose tolerance test showed normal patterns of blood glucose clearance 1 month after transplantation. It can be concluded that the prevascularized PET mesh bag enabled transplanted BAP to survive and maintain function, thus indicating a potential site for BAP transplantation.

Nano Letters, 2008

Encapsulation of cells and tissue offers a rational approach for attenuating deleterious host res... more Encapsulation of cells and tissue offers a rational approach for attenuating deleterious host responses toward transplanted cells, but a need exists to develop cell encapsulation strategies that minimize transplant volume. In this report, we describe the formation of nanothin, PEG-rich conformal coatings on individual pancreatic islets via layer-by-layer self-assembly of poly(L-lysine)-g-poly(ethylene glycol)(biotin) (PPB) and streptavidin (SA). Through control of grafting ratio, PPB could be rendered nontoxic and facilitated growth of PPB/SA multilayer thin films that conformed to the heterogeneous islet surface. (PPB/SA) 8 multilayer films could be assembled without loss of islet viability or function, and coated islets performed comparably to untreated controls in vivo in a murine model of allogenic intraportal islet transplantation. Islet transplantation has emerged as a promising treatment for diabetes. 1 However, widespread clinical application of islet transplantation remains limited, in part, by the deleterious side effects of immunosuppressive therapy necessary to prevent host rejection of transplanted cells. 2 Decades of extensive research have led to the development of semipermeable microcapsules capable of protecting donor cells from the host immune system while allowing transport of glucose, insulin, and other essential nutrients. 3-5 To date, most microencapsulation approaches have employed 400-800 µm diameter microcapsules of diverse composition, formed via various drop generating processes, to randomly entrap 50-250 µm diameter islets. 4,6,7 Unfortunately, the relatively large size of conventional microcapsules imposes consequential mass transport limitations and produces transplant volumes not suitable for infusion into the portal vein of the liver, 8-10 the clinically preferred and currently most successful site for islet transplantation. 1,11 Consequently, most microencapsulated islets are transplanted into sites with a limited vascular supply, such as the omentum 12 or peritoneal cavity, 13-15 which ultimately contributes to cell hypoxia and subsequent graft failure. 16 Therefore, encapsulation strategies for intraportal islet transplantation must minimize capsule void volume. To reduce capsule size, several investigators have developed approaches to deposit coatings of defined thickness that conform to the surface of individual islets. 17-20 Transplant volume

Journal of Vascular Surgery, 2006

Background: CD39 (nucleoside triphosphate diphosphohydrolase [NTPDase-1]) expressed on the lumina... more Background: CD39 (nucleoside triphosphate diphosphohydrolase [NTPDase-1]) expressed on the luminal surface of endothelial cells rapidly metabolizes extracellular adenosine triphosphate (ATP) and adenosine diphosphate (ADP) to adenosine monophosphate (AMP), and abrogates platelet reactivity. Optimization of CD39 enzymatic activity appears dependent upon the expression of both transmembrane domains within plasma membranes. Thus, motivation exists to examine therapeutic antiplatelet formulations that consist of liposomal CD39. Methods: Full-length human CD39 was produced by using a yeast expression system, purified, and reconstituted within lipid vesicles. The catalytic efficiency (kcat/Km) of CD39-mediated phosphohydrolysis of ADP and ATP was determined both for detergent-solubilized and protein-reconstituted CD39 within lipid membranes. The capacity of CD39containing lipid vesicles to inhibit platelet activation induced by ADP, collagen, or thrombin was determined in vitro by platelet aggregometry. A murine model of thromboplastin-induced thromboembolism was used to determine the effectiveness of intravenous liposomal CD39 in limiting platelet consumption and mortality. Results: Reconstitution of human CD39 in lipid vesicles was associated with a decrease in Km of nearly an order of magnitude over the detergent-solubilized form. There was a concomitant increase in both ADPase and ATPase catalytic efficiencies (kcat/Km ADPase: sol CD39: 2.7 ؋ 10 6 vs liposomal CD39: 1.4 ؋ 10 7 min/ M; kcat/Km ATPase: sol CD39: 7.2 ؋ 10 6 vs liposomal CD39: 2.0 ؋10 7 min/M). Furthermore, CD39 lipid vesicles effectively inhibited platelet aggregation when activated by ADP, collagen, or thrombin, and also promoted platelet disaggregation (60.4% ؎ 6.1%). Treatment with CD39 lipid vesicles preserved platelet counts after thromboplastin injection (pretreatment, 906.8 ؎ 42.9 platelets/m 3 ; empty vesicles, 278.6 ؎ 34.8 platelets/m 3 ; CD39 vesicles, 563.6 ؎ 42.2 platelets/m 3 ; n ‫؍‬ 10 mice/test group; P < .0001). In parallel survival studies, liposomal CD39 reduced mortality from 73% to 33% (P < .05; n ‫؍‬ 12 mice/experimental test group, n ‫؍‬ 15 mice/control test group). Conclusions: Incorporation of solubilized CD39 into a lipid bilayer restores enzyme activity and optimizes thromboregulatory potential. Treatment with CD39 in liposomal formulations decreased mortality in a murine model of thromboplastin-induced thromboembolism by limiting intravascular platelet aggregation and thrombosis. (J Vasc Surg 2006;43: 816-23.) Clinical Relevance: Platelets express at least three distinct purinergic receptors that bind ADP, only one of which is blocked by oral thienopyridine derivatives, such as clopidogrel. In this report, we demonstrate that CD39 liposomal formulations rapidly metabolize ADP to AMP and effectively inhibit platelet activation and aggregation in vitro and in vivo. CD39 liposomal formulations may provide a useful therapeutic option either alone or in combination with other existing antiplatelet regimens to treat acute vascular syndromes characterized by platelet thrombus formation, such as stroke or acute lower-extremity ischemia.

Journal of the American Chemical Society, 2011

Layer-by-layer assembly of polyelectrolyte multilayer (PEM) films represents a bottom-up approach... more Layer-by-layer assembly of polyelectrolyte multilayer (PEM) films represents a bottom-up approach for reengineering the molecular landscape of cell surfaces with spatially continuous and molecularly uniform ultrathin films. However, fabricating PEMs on viable cells has proven challenging owing to the high cytotoxicity of polycations. Here, we report the rational engineering of a new class of PEMs with modular biological functionality and tunable physicochemical properties which have been engineered to abrogate cytotoxicity. Specifically, we have discovered a subset of cationic copolymers that undergoes a conformational change, which mitigates membrane disruption and facilitates the deposition of PEMs on cell surfaces that are tailorable in composition, reactivity, thickness, and mechanical properties. Furthermore, we demonstrate the first successful in vivo application of PEM-engineered cells, which maintained viability and function upon transplantation and were used as carriers for in vivo delivery of PEMs containing biomolecular payloads. This new class of polymeric film and the design strategies developed herein establish an enabling technology for cell transplantation and other therapies based on engineered cells.