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Li-He Guo

Publications and source records attributed to Li-He Guo.

12 recordsLinked to original sources
PubMed2004

Cognitive impairment in mice over-expressing gamma-aminobutyric acid transporter 1 (GAT1).

There is increasing evidence that GABAergic system plays an important role in the neural control of learning and memory processes. GAT1 over-expressing mice (NA) were generated, in which GAT1 is under the control of a neuron-specific enolase (NSE) promoter, to investigate effects of GABA transporter on cognitive function. Our results revealed that NA mice displayed cognitive deterioration in associative learning ability and new object recognition retention, compared with the wild-type littermates (WT2). However, the impaired cognitive function of transgenic mice could be rescued after chronic administration of GAT1 selective inhibitor for 6 days. In addition, there was no change of the expression of NMDA receptors in NA mice. Taken together, we show a potentially important role for GAT1 in the neural control of cognitive processes, and indicate great potential for GAT1 as a clinical target of cognitive disorders.

Animals↗
PubMed2004

Direct transfer of A20 gene into pancreas protected mice from streptozotocin-induced diabetes.

AIM: To investigate the efficiency of transfer of A20 gene into pancreas against STZ-induced diabetes. METHODS: PVP-plasmid mixture was directly transferred into the pancreatic parenchyma 2 d before STZ injection. The uptake of plasmid pcDNA3-LacZ or pcDNA3-A20 was detected by PCR and the expression of LacZ was confirmed by histological analysis with X-gal. A20 expression in the pancreas of pcDNA3-A20 transgenic mice was measured by RT-PCR and Western blots. Urine amylase, NO generation, and histological examination were examined. RESULTS: Injection of PVP-plasmid mixture directly into the pancreatic parenchyma increased urine amylase concentration 16 h after operation and reversed it to nearly normal 36 h later. On d 33 LacZ expression could be found in spleen, duodenum, and islets. The development of diabetes was prevented by direct A20 gene transferring into the pancreas and A20-mediated protection was correlated with suppression of NO production. The insulitis was ameliorated in A20-treated mice. CONCLUSION: Injection of PVP-plasmid mixture directly into the pancreatic parenchyma led to target gene expression in islets. Direct transfer of A20 gene into the pancreas protected mice from STZ-induced diabetes.

Amylases↗
PubMed2003

Decrease of morphine-induced reward effects and withdrawal symptoms in mice overexpressing gamma-aminobutyric acid transporter I.

Morphine addiction has been shown to result from neural adaptations produced by repeated drug exposure, but the mechanism is still unclear. In the present study, we found that gamma-aminobutyric acid (GABA) uptake was increased in mouse brain 120 min after, but not 20 min after, morphine (10 mg/kg, s.c.) injection. We generated GABA transporter I (GAT1)-overexpressing mice to investigate whether the GABAergic system and GABA transporter are involved in morphine-induced reward effects and withdrawal symptoms. Our results revealed that the rewarding effects induced by morphine were significantly decreased in GAT1-overexpressing mice as measured by the conditioned place preference (CPP) paradigm. Moreover, both somatic and vegetative signs of naloxone-induced morphine withdrawal symptoms were substantially reduced in GAT1-overexpressing mice. In addition, the decreased morphine rewarding in transgenic mice could be recovered when mice were coinjected with NO-711 (a GAT1 selective inhibitor) in the CPP paradigm. These findings suggest that the GABAergic system plays an important role in morphine addiction and point to the possibility of developing drugs that target GAT1 and extend the clinical application of opiates.

Adaptation, Physiological↗
PubMed2003

Hyperalgesic effects of gamma-aminobutyric acid transporter I in mice.

The present study focused on the involvement of gamma-aminobutyric acid transporter I (GAT1) in pain. We found that GABA uptake was increased in mouse spinal cord at 20 min and 120 min after formalin injection and in mouse brain at 120 min, but not 20 min, after formalin injection. In addition, the antinociceptive effects of GAT1-selective inhibitors were examined using assays of thermal (tail-flick) and chemical (formalin and acetic acid) nociception in C57BL/6J mice. The GAT1-selective inhibitors, ethyl nipecotate and NO-711, exhibited significant antinociceptive effects in these nociceptive assays. To study further the effects of GAT1 on pain, we used two kinds of GAT1-overexpressing transgenic mice (under the control of a CMV promoter or a NSE promoter) to examine the nociceptive responses in these mice. In the thermal, formalin, and acetic acid assays, both kinds of transgenic mice displayed significant hyperalgesia after nociceptive stimuli. In addition, the micro opioid receptor antagonist naloxone had no influence on nociceptive responses in wild-type and transgenic mice. The results indicate that GAT1 is involved in the regulation of pain processes, and point to the possibility of developing analgesic drugs that target GAT1 other than opioid receptors.

Analgesics, Opioid↗
PubMed2003

Intramuscular injection of interleukin-10 plasmid DNA prevented autoimmune diabetes in mice.

AIM: To investigate the effect of plasmid coding interleukin-10 (IL-10) DNA on the development of autoimmune diabetes induced by multiple low doses of streptozotocin (STZ) in mice. METHODS: Injection of STZ (40 mg/kg, i.p.) was given daily for five consecutive days. pcDNA3-IL-10 plasmid (IL-10-treated group) or pcDNA3-null plasmid (pcDNA3-null-treated group) (100 microg DNA once a day) were injected into skeletal muscles of mice on d 1 and d 14. Blood glucose concentration was measured. After mice were killed on d 28, serum IFN-gamma level was measured by ELISA, and pancreatic IL-1beta and TNF-alpha mRNA expression was detected by semi-quantitative reverse-transcription PCR (RT-PCR). The number of CD4+ and CD8+ lymphocytes from spleen was detected using FACS. In addition, pancreatic histology was measured for determination of insulitis grades. RESULTS: Treatment with pcDNA3-IL-10 resulted in the retention and expression of the vector in skeletal muscle, associated with a considerable elevation in the plasma level of IL-10, which was not observed in pcDNA3-null-treated mice. In IL-10-treated diabetic mice induced by STZ, delay-type hypersensitivity responses were suppressed and the glucose level was greatly lower on d 14, 21, and 28 than pcDNA3-null-treated group (P<0.05 or P<0.01). On d 21 and 28 the incidence of diabetes was 33.3% and 40.0%, respectively, which was markedly lower than that of pcDNA3-null-treated group (P<0.05). In IL-10-treated mice pancreatic IL-1beta and TNF-alpha mRNA expression was depressed, and serum IFN-gamma concentration and the number of spleen CD4+ or CD8+ lymphocytes were decreased on d 28. The insulitis grades of IL-10-treated mice were lower than that of pcDNA3-null-treated group (P<0.01). CONCLUSION: Systemic administration of IL-10 plasmid DNA can alleviate insulitis of experimental autoimmune diabetes in mice and reduce incidence of diabetes.

Animals↗
PubMed2003

Human alpha galactosidase and alpha 1,2 fucosyltransferase concordantly inhibit xenoreactivity of NIH 3T3 cells with human serum.

AIM: To study the influence of the expression of human alpha galactosidase and alpha1,2 fucosyltransferase on Gal alpha 1,3 Gal and consequent xenoreactivity in NIH3T3 cells. METHODS: The expression levels of G antigen and H antigen and binding of human natural antibodies (IgG and IgM) and complement (C3c) to NIH3T3 cells were analyzed by flow cytometry. Western blot was employed to further determine the expression of glycoproteins of G antigen. Cytolysis assay with normal human serum was performed by MTT assay. RESULTS: Western blot showed that glycoproteins with molecular weight of 107 kDa, 98 kDa, 88 kDa, 56 kDa, 40 kDa, and 37 kDa were inhibited and even abrogated totally in alpha galactosidase transfectants and alpha 1,2 fucosyltransferase transfectants. The combined transfection of the two enzymes led to a much stronger inhibition of the glycoproteins. The binding of GS-IB4 was decreased by 57.4 % in alpha galactosidase transfectants, 28.8 % in alpha 1,2 fucosyltransferase transfectants, and 72.1 % in combined transfectants, respectively. In contrast, UEA-1 binding was increased about 6.7-fold, 6.0-fold, and 8.0-fold respectively. The xenoreactivity with human IgG was also reduced by 61.4 %, 67.0 %, and 73.4 %, respectively in the three kinds of transfectants. The resistance to cytolysis mediated by human serum was enhanced by 42.4 % in alpha galactosidase transfectants, 51.9 % in alpha 1,2 fucosyltranferase, and even 65.5 % in the combined transfectants. CONCLUSION: Although alpha galactosidase and alpha 1,2 fucosyltransferase had different biochemical properties, they could inhibit the expression of Gal alpha 1,3 Gal synergistically, leading to stronger resistance of xenograft against cytolysis.

3T3 Cells↗
PubMed2003

Gene therapy of experimental autoimmune thyroiditis mice by in vivo administration of plasmid DNA coding for human interleukin-10.

AIM: To investigate the effect of interleukin-10 (IL-10) gene on experimental autoimmune thyroiditis mice. METHODS: Mice were immunized to induce autoimmune thyroiditis with porcine thyroglobulin (pTg), and thyroids of mice were injected with IL-10 DNA. On d 28 after immunization with pTg, mRNA expression of IL-10 in thyroid glands was detected and thyroid specimens were histopathological studied. RESULTS: The mRNA expression of IL-10 was detected in thyroid glands on d 7 and 14 after injection of IL-10 plasmid DNA or on COS-7 cells 48 h after IL-10 plasmid DNA transfection. In addition, hIL-10 levels in culture media significantly increased 48 h and 72 h after IL-10 plasmid DNA transfection. Infiltration index of lymphocytes (1.1+/-0.4) in thyroids of IL-10-treated mice was significantly lower than that of pcDNA3-null-treated mice (2.2+/-0.5) (P<0.01). Compared with pcDNA3-null control mice, IL-10-treated mice had lower levels of serum IFN-gamma (P<0.01). CONCLUSION: The direct injection of DNA expression vectors encoding IL-10 into thyroid significantly inhibited development of lymphocytic infiltration of thyroid of autoimmune thyroiditis mice, and alleviated the progression of this disease.

Animals↗
PubMed2003

Dopaminergic trophism after intrastriatal injection of lentivirus-transferred GDNF in Parkinson rat model.

To investigate the effects of lentivirus-mediated transfection of GDNF on Parkinson s disease (PD). The pNL-gdnf plasmid was constructed by replacing the LacZ-coding region present in pNL-lacZ/CMV. Vector particles involved a three-plasmid lentivirus expression system were co-transferred into 293T cells through calcium phosphate method. High-titer virus was collected from infected 293T cells and injected into lesion-side striatum of PD rats, and their apomorphine-induced rotations were assayed at day 14, 30 and 60, respectively. GDNF protein was detected by Western blot analysis, and the expression of lacZ and TH were detected by immunochemistry. Results showed that behavioral recovery gradually appeared after transplantation, and a significant reduction in the rotational response was observed at the 14th day. Meanwhile, gdnf expression maintained for at least 60 d, which had dopaminergic trophism to a certain degree, indicating that lentivirus-mediated transfection gdnf could effectively improve the clinical function of PD rats, which provide a potential attractive tool of gene therapy for PD.

Animals↗
PubMed2003

Expression of human alpha-galactosidase leads to reduction of major xenoepitope Galalpha(1,3) Gal in NIH 3T3 cell.

AIM: To examine the effects of the expression of alpha-galactosidase on the expression of the major xenoepitope Galalpha(1,3) Gal (G antigen) in NIH 3T3 cell. METHODS: The expression levels of G antigen and H antigen and binding of human natural antibodies (IgG and IgM) and complement (C3c) to NIH 3T3 cells were analyzed by flow cytometry. Western blot was employed to further determine the expression of glycoproteins of G antigen. Cytolysis assay with normal human serum was performed by MTT assay. RESULTS: In transfectants, Western blot showed that the binding of human IgG to glycosylated proteins located on the cell membrane was decreased, even abrogated totally. Together with the reduced binding of Gs-IB4 (Griffonia simplicifolia) to transfectants, the stable expression of human alpha-galactosidase effectively inhibited Galalpha(1,3) Gal, Gal epitope synthesis in NIH 3T3 cell. As a result, the xenoreactivities of human IgG, IgM, and C3c were reduced by 73.4 %, 22.3 % and 47.9 %, respectively, while the cell lysis mediated by human XNA and complements was decreased by 42.4 %. CONCLUSION: The stable expression of human alpha-galactosidase in NIH 3T3 cell strongly inhibits the expression of Gal epitopes, resulting in abrupt reduction in xenorejection induced by human serum.

Animals↗
PubMed2003

Increase in drug-induced seizure susceptibility of transgenic mice overexpressing GABA transporter-1.

AIM: The changes of seizure susceptibility of transgenic mice overexpressing GABA transporter-1 (GAT-1) were studied to clarify the possible role of GABAergic transmission in epileptogenesis. METHODS: Seizures were induced by intraperitoneal administration of pentylenetetrazol (PTZ), picrotoxin (PIC), or kainic acid (KA) respectively. The anticonvulsant effect of ethyl nipecotate was tested by its intraperitoneal injection 15 min before the administration of the epileptogenic agents. RESULTS: The percentages of occurrence of clonic seizures induced by PTZ 45 mg/kg, PIC 2.5 mg/kg, or KA 20 mg/kg in GAT-1 transgenic mice were 88.9 %, 100 %, and 83.3 % respectively, whereas those in control C57BL/6J mice were 42.9 %, 57.1 %, and 33.3 %. The percentages of occurrence of tonic seizures induced by PTZ 45 mg/kg, PIC 2.5 mg/kg, or KA 20 mg/kg in transgenic mice were 88.9 %, 100 %, and 83.3 % respectively, and whereas those in control mice were 28.6 %, 42.9 %, and 16.7 %. The latencies of both clonic and tonic seizures onset in transgenic mice were markedly shortened compared with those in control animals. The results indicated that GAT-1 transgenic mice showed increased susceptibility to seizures induced by the anti-GABAergic convulsive drugs (PTZ, PIC), as well as glutamic receptor agonist (KA). Ethyl nipecotate, inhibitor of GAT-1, inhibited PTZ-induced seizures in both GAT-1 transgenic and C57BL/6J mice. The incidence of seizures was decreased after the application of ethyl nipecotate, and the latencies to the onset of clonic or tonic seizures were also prolonged. CONCLUSION: The increase in seizure susceptibility of transgenic mice over-expressing GAT-1 is an evidence for involvement of GABAergic transmission in epileptogenesis, and this transgenic mouse might be a useful animal model for study on the role of GABAergic transmission in epileptogenesis.

Animals↗
PubMed2003

CMV-hFasL transgenic mice are sensitive to low doses of streptozotocin-induced type I diabetes mellitus.

AIM: To investigate the role of Fas-FasL pathway in the pathogenesis of streptozotocin (STZ)-induced type I diabetes mellitus. METHODS: Low dose injections of STZ were used to induce type I diabetes mellitus in the CMV-hFasL transgenic mice. Blood glucose concentration was measured with Glucotrand Plus blood glucose test strips. Expression of hFasL was detected by RT-PCR and Western blotting. The severity of insulitis was determined by histological examination. Expressions of IL-1beta and TNF-alpha mRNA in the pancreas were detected by semi-quantitative RT-PCR analysis. Fas expression in apoptotic RIN-5F cells was also confirmed by RT-PCR in vitro. RESULTS: hFasL was expressed in the islets of CMV-hFasL transgenic mice. The transgenic mice were sensitive to diabetic induction than the control WT mice. IL-1beta and TNF-alpha expressions in the pancreas of CMV-hFasL transgenic mice were far more than that in WT mice. We also found STZ and IL-1beta could both induce higher expression of Fas in RIN-5F. The combining of Fas-FasL could lead to the apoptosis of beta cells in the CMV-hFasL transgenic mice. CONCLUSION: Fas-FasL interaction plays a significant role in the pathogenic mechanism of type I diabetes mellitus.

Animals↗