Are you Zheng-Shan Zhao?

Claim your profile

Publications (3)11.53 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Previous studies demonstrating the efficacy of insulin gene therapy have mostly involved use of adenoviral vectors or naked DNA to deliver the insulin gene. However, this procedure may not guarantee long-term insulin production. To improve the performance, we prepared recombinant adeno-associated viral vectors (rAAV) harboring the gene encoding a furin-modified human insulin under the cytomegalovirus (CMV) promoter [rAAV-hPPI(F12)]. Streptozotocin (STZ)-induced diabetic Sprague-Dawley rats were used as a diabetic animal model. The levels of blood glucose, insulin, and HbA1c were measured to test the effect. An intraperitoneal glucose tolerance test was performed to test the capability of blood glucose disposal. Immunohistochemical staining and Northern blot analyses were performed to survey the expression pattern of the therapeutic insulin gene. STZ-induced diabetic Sprague-Dawley rats infused via the portal vein with rAAV-hPPI(F12) produced human insulin and after a 6-h fast were normoglycemic for over 90 days post-treatment, whereas diabetic rats treated with recombinant adenoviral vector harboring the hPPI(F12) gene [rAV-hPPI(F12)] were normoglycemic only for days 3 to 13 post-treatment. Insulin mRNA was detected mainly in the liver of the rAAV-hPPI(F12)-treated diabetic rats. The glucose tolerance capability of the rAAV-hPPI(F12)-treated diabetic rats was comparable to that of non-diabetic rats, even without injection of recombinant insulin. Furthermore, blood HbA1c concentrations in rAAV-hPPI(F12)-treated diabetic rats were reduced to almost the normal level. Importantly, studies of rAV or rAAV vector-dependent side effects on the targeted liver strongly suggested that only rAAV treatment caused no side effects. These results demonstrate that our rAAV-mediated in vivo insulin gene therapy provides safer maintenance of the insulin gene expression required for long-term and thus more effective blood glycemic control.
    The Journal of Gene Medicine 06/2005; 7(5):621-9. · 2.16 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To clarify the paradoxic effects of cerulenin, namely its in vitro inhibitory effects on fat catabolism and its in vivo reduction of fat mass, we studied the in vivo and in vitro effects of cerulenin on carnitine palmitoyltransferase-1 (CPT-1) activity, the rate-limiting enzyme of fatty acid oxidation. A single ip injection of cerulenin significantly reduced body weight and increased core temperature without significantly reducing food intake. In situ hybridization study revealed that a single injection of cerulenin did not affect the expression of orexigenic neuropeptide mRNA. Cerulenin's effect on CPT-1 activity was biphasic in the liver and muscle: early suppression during the first 1 h and late stimulation in the 3-5 h after ip treatment. In vitro cerulenin treatment reduced CPT-1 activity, which was overcome by cotreating with catecholamine. Intracerebroventricular injection of cerulenin increased CPT-1 activity significantly in soleus muscle, and this effect was sustained for up to 3 h. Pretreatment with alpha-methyl-p-tyrosine inhibited the cerulenin-induced increase in core temperature and the late-phase stimulating effect of cerulenin on CPT-1 activity. In adrenalectomized mice, cerulenin also increased the activity. In vivo cerulenin treatment enhanced muscle CPT-1 activity in monosodium glutamate-treated arcuate nucleus lesioned mice but not in gold thioglucose-treated ventromedial hypothalamus lesioned mice. These findings suggest that cerulenin-induced late-phase stimulating effects on CPT-1 activity and energy expenditure is mediated by the activation of innervated sympathetic nervous system neurons through the firing of undefined neurons of the ventromedial hypothalamus, rather than the arcuate nucleus.
    Endocrinology 08/2004; 145(7):3197-204. · 4.72 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: MCD (malonyl-CoA decarboxylase), which catalyses decarboxylation of malonyl-CoA, is known to play an important role in the regulation of malonyl-CoA concentration. Recently, it has been observed that the expression of MCD is significantly decreased in the hearts of the PPARalpha (peroxisome-proliferator-activated receptor alpha) (-/-) mice, where the rate of fatty-acid oxidation is decreased by the increased malonyl-CoA level [Campbell, Kozak, Wagner, Altarejos, Dyck, Belke, Severson, Kelly and Lopaschuk (2002) J. Biol. Chem. 277, 4098-4103]. This suggests that MCD may be transcriptionally regulated by PPARalpha. To investigate whether PPARalpha is truly responsible for transcriptional regulation of the rat MCD gene, transient reporter assay was performed in CV-1 cells. The promoter activity was increased by 17-fold in CV-1 cells co-transfected with PPARalpha/retinoid X receptor alpha expression plasmid. In sequence analysis of the promoter region, three putative PPREs (PPAR response elements) were identified, and promoter deletion analysis showed that PPRE2 and PPRE3 were functional. Electrophoretic mobility-shift assays revealed that PPARalpha/retinoid X receptor alpha heterodimer indeed bound to the two PPREs, and the binding specificity of PPARalpha on PPRE was also confirmed by experiments with mutated oligonucleotides. These results indicate that the elements behaved as a responsive site to PPARalpha activation. MCD mRNA levels in WY14643-treated rat hepatoma cells as well as in the liver of fenofibrate-fed Otsuka Long-Evans Tokushima fatty rats were also found to be increased, suggesting that PPARalpha can activate the rat hepatic MCD transcription by binding to the PPREs in the promoter. We propose that MCD performs an important role in understanding the regulatory mechanism between activated PPARalpha and fatty-acid oxidation by altering the malonyl-CoA concentration.
    Biochemical Journal 04/2004; 378(Pt 3):983-90. · 4.65 Impact Factor