Biomedical subjects

Lihui Liu

Publications and source records attributed to Lihui Liu.

5 recordsLinked to original sources

PubMed2006

Ex vivo expansion and in vivo infusion of bone marrow-derived Flk-1+CD31-CD34- mesenchymal stem cells: feasibility and safety from monkey to human.

Flk-1(+)CD31(-)CD34(-) mesenchymal stem cells (MSCs) are multipotent cells with extensive proliferation ability and immunomodulatory function. On the basis of our previous work showing their potential application in tissue engineering and immune diseases, we designed a preclinical and Phase I trial to evaluate the feasibility and safety of intravenous infusion of these cells after ex vivo expansion. Rhesus monkey and human Flk-1(+)CD31(-)CD34(-) MSCs were isolated from bone marrow and passaged a maximum of six passages. Karyotype analysis showed Flk-1(+)CD31(-)CD34(-) MSCs remained normally diploid within six passages of expansion. Expanded cells were transplanted into rhesus monkeys and human volunteers, respectively. During the infusion of these cells, the life signs of the recipients were normal. Laboratory tests for blood, bone marrow, kidney, and liver function were conducted and no significant changes were observed before and after cell infusion. Identification of the sry sequence from the male donor in female recipients showed that allogeneic rhesus Flk- 1(+)CD31(-)CD34(-) MSCs were capable of homing to and establishing residence within the recipients' bone marrow. No significant changes were observed in lymphocyte cell subpopulation before and after infusion. These result showed that Flk-1(+)CD31(-)CD34(-) MSCs have no obvious side effects after intravenous administration, encouraging investigators to perform further studies in stem cell therapy.

Adult↗

PubMed2005

RhoA acts downstream of Wnt5 and Wnt11 to regulate convergence and extension movements by involving effectors Rho kinase and Diaphanous: use of zebrafish as an in vivo model for GTPase signaling.

Gastrulation shapes the early embryos by forming three germ layers, ectoderm, mesoderm and endoderm. In vertebrates, this process requires massive cell rearrangement including convergence and extension (CE) movements that involve narrowing and lengthening of embryonic tissues as well as cell elongation. Such polarization and movements require precise reorganization and regulation of the cytoskeleton network and cell adhesion. Rho small GTPases are key regulators for dynamic actin cytoskeleton. However, the signaling mechanisms underlying their functions in CE remain to be further elucidated. We have cloned the zebrafish Danio rerio rhoA and by capitalizing on the specific functional knockdown using morpholinos against rhoA and the availability of CE mutants defective in Wnt signaling, we showed that rhoA morphants were reminiscent to noncanonical wnt mutants with serious disruption in CE movements. Injection of rhoA mRNA effectively rescued such defects in wnt5 and wnt11 mutants. Furthermore, CE defects in rhoA knockdown or wnt mutants can be suppressed through functional bypass after ectopic expression of the two mammalian Rho effectors, the Rho kinase and Diaphanous (mDia). These results provide the first evidence that the RhoA in vivo acts downstream of Wnt5 and Wnt11 to effect, without affecting cell fates, on the CE movements in zebrafish embryos. Significantly, it elicits such effect via both effectors, Rho kinase and Dia. These findings also support the versatility of the zebrafish as a model to further investigate the roles of various classes of small GTPases in regulating cell dynamics in vivo.

Amino Acid Sequence↗

PubMed2004

Quadruple-wavelength actively mode-locked fiber laser with polarization-controlled wavelength switching.

An actively mode-locked fiber laser with two overlapping cavities is proposed and successfully demonstrated to generate switchable quadruple-wavelength picosecond pulses. The wavelengths are specified by two Bragg gratings in polarization-maintaining and absorption-reducing fiber. By simple adjustment of two polarization controllers, the proposed laser can be made to operate at quadruple wavelength or to switch between wavelengths at room temperature. For wavelength switching, four single-wavelength, six dual-wavelength, and four triple-wavelength operations were performed without changing the repetition rate of the output pulses.

Journal Article↗

PubMed2002

Platelet-derived growth factor A (pdgf-a) expression during zebrafish embryonic development.

Zebrafish pdgf-a gene was cloned and its expression pattern studied during zebrafish embryogenesis. Zebrafish pdgf-a mRNA was present at high levels in fertilized eggs as well as in all embryonic cells up to the end of gastrulation. Spatially restricted expression started after the onset of segmentation and was mainly localized in the developing pharyngeal arches. Transient expression was also detected in Kupffer's vesicle, a teleost-specific structure, and in lateral trunk and tail regions surrounding the neural keel, as well as areas of the developing pronephros.

Amino Acid Sequence↗

PubMed2002

Platelet-derived growth factor receptor alpha (pdgfr-alpha) gene in zebrafish embryonic development.

Here we present the cloning of a full-length zebrafish pdgfr-alpha cDNA as well as the expression of this gene during zebrafish embryogenesis. We show that zebrafish pdgfr-alpha mRNA is present at high levels in the fertilized egg as well as in all embryonic cells up to the end of gastrulation. Spatially restricted expression of the gene started after the onset of segmentation and is mainly localized in premigratory neural crest cells, the placodes, the anterior paraxial cells of somites and the adaxial cells of the tailbud. Transient expression of this gene was also detected in the early Kupffer's vesicle, a teleost-specific structure. Expression of the zebrafish pdgfr-alpha is both conserved as well as diverged comparing to that of other vertebrate species.

Animals↗