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Biomedical subjects

H F Zhao

Publications and source records attributed to H F Zhao.

At least 19 recordsLinked to original sources
PubMed2005

Anti-monocyte chemoattractant protein 1 gene therapy attenuates experimental chronic pancreatitis induced by dibutyltin dichloride in rats.

BACKGROUND: Monocyte chemoattractant protein 1 (MCP-1) is a member of the C-C chemokine family and exerts strong chemoattractant activity in monocytes, macrophages, and lymphocytes. Rat pancreatic fibrosis induced by dibutyltin dichloride (DBTC) is considered to be an appropriate chronic pancreatitis model histologically and enzymatically, as has demonstrated in a previous study. AIM: We examined the effect of human dominant negative inhibitor of MCP-1 (mutant MCP-1) on progression of chronic pancreatitis induced by DBTC in a rat model. METHODS: We used the experimental model of chronic pancreatitis induced by DBTC in rats. Mutant MCP-1 or empty plasmid at a dose of 50 microg/body weight was administrated into rat thigh muscles on days 4, 11, and 18 after administration of DBTC. On days 14 and 28, we evaluated the effect of mutant MCP-1 morphologically and biochemically. RESULTS: The mutant MCP-1 treated group inhibited early pancreatic inflammation and later pancreatic fibrosis histologically, and showed a decrease in serum MCP-1 concentration, intrapancreatic hydroxyproline, alpha-smooth muscle actin, and an increase in intrapancreatic amylase and protein content compared with the empty plasmid treated group. The mutant MCP-1 group also inhibited intrapancreatic mRNA expression of cytokines and chemokines. CONCLUSIONS: : Our findings suggest that monocyte/macrophage recruitment and the systemic MCP-1 signal pathway contribute to progression of chronic pancreatitis, and that blockade of MCP-1 may suppress the development of pancreatic fibrosis.

Actins↗
PubMed2001

Transcriptional activity of the SHP-1 gene in MCF7 cells is differentially regulated by binding of NF-Y factor to two distinct CCAAT-elements.

Our previous studies have shown that SHP-1, a SH2 domain-containing protein-tyrosine phosphatase, is expressed not only in cells of hematopoietic lineages, but also in many non-hematopoietic cells under the control of an alternative tissue-specific promoter, P1. In this study, the activity of the P1 promoter was analyzed in a region spanning 3.5 kb upstream of the major transcription start site in non-hematopoietic MCF-7 cells. Using DNA footprinting, gel retardation assays and mutational analysis, we have characterized cis-regulatory elements that are essential to confer the P1 promoter activity. An upstream Sp1 element (-126 to -118) positively regulated this TATA-box-lacking promoter. Two inverted CCAAT-elements (-332 to -328 and -66 to -62) played important roles in regulating the SHP-1 gene expression, and transcription factor NF-Y predominantly bound to the two CCAAT-elements. Binding of NF-Y to the distal CCAAT-element enhanced the transcriptional activity of the P1 promoter. In contrast, binding of NF-Y to the proximal CCAAT-element and interacting with repressor(s) inhibited the promoter activity. Furthermore, incubation of MCF7 cells with 100 ng/ml trichostatin A, an inhibitor of histone deacetylase, significantly increased the activity of the P1 promoter. Mutation in the proximal CCAAT-element, however, eliminated the activating effect of trichostatin A on the promoter. Together, our data suggest that NF-Y factor can function either as a specific positive or negative regulator of P1 promoter activity in non-hematopoietic MCF7 cells.

Base Sequence↗
PubMed2001

[Studies on the chemical constituents from Tribulus terrestris].

AIM: To investigate the chemical constituents of the fruit of Tribulus terrestris J.. METHODS: Various chromatographic techniques were used to separate the chemical constituents. ESIMS, IR, 1HNMR, 13CNMR and HMBC were used to determine the structures of the isolated constituents. RESULTS: Two new compounds were isolated from the fruits of Tribulus terrestris J. and were identified as neohecogenin-3-O-beta-D-glucopyranosyl (1-->2)-beta-D-glucopyranosyl (1-->4)-beta-D-galactopyranoside (I); neohecogenin-3-O-beta-D-glucopyranosyl (1-->4)-beta-D-galactopyranoside (II). CONCLUSION: Compounds I and II are new steroidal saponins.

Fruit↗
PubMed1999

[Effects of orally available prodrug of cromoglycic acid on collagen-induced arthritis mice].

Cromoglicate lisetil (CL) is an orally deliverable prodrug of cromoglycic acid, having diethyl promoieties and a lysyl promoiety for its optimum drug-delivery. We examined the effects of CL on bovine type II collagen (CII)-induced arthritis (CIA) of male DBA/1J mice, an experimental model for human rheumatoid arthritis, and its action mechanism. CL (100 mg/kg/day) was given by gavage to CII-immunized mice once daily for 6 weeks, starting when arthritic symptoms became evident. Symptomatic scores of arthritis obviously elevated in non-treated CIA mice at week 6.5 after initial immunization and continued elevated thereafter throughout the experiment, the elevation which was reduced by CL. CL also improved radiographic score of phalangeal destruction and pathohistological indexes at the end of treatment period. Serum anti-CII antibody titer was increased in non-treated CIA mice and the elevation was reduced by CL treatment. Mast cells (MCs) number in arthritic region was increased in non-treated CIA mice but not by CL treatment. In conclusion, oral CL treatment proved beneficial in CIA mice. Observed correlation between the CL effect on CIA and that on MCs number suggests the potential contribution of MCs to accelerate chronic arthritic processes and may further implicate potential action mechanism of CL, which may act by regulating MC functions for chronic inflammation.

Administration, Oral↗
PubMed1998

IRE-ABP (insulin response element-A binding protein), an SRY-like protein, inhibits C/EBPalpha (CCAAT/enhancer-binding protein alpha)-stimulated expression of the sex-specific cytochrome P450 2C12 gene.

In primary hepatocytes, overexpression of an insulin response element-A binding protein (IRE-ABP), a member of the SRY family of high-mobility group (HMG) proteins, inhibits CCAAT/enhancer-binding protein alpha (C/EBPalpha)-mediated activation of the female-specific cytochrome P450 2C12 (CYP2C12) gene, but not the male-specific cytochrome P450 2C11 (CYP2C11) gene. IRE-ABP and C/EBPalpha have overlapping specificity for the C/EBPalpha target site in the CYP2C12 promoter and compete for binding to CYP2C12 DNA in vitro. In contrast, IRE-ABP and C/EBPalpha bind distinct sequences in the CYP2C11 promoter. A single amino acid substitution in the HMG domain of IRE-ABP impairs its ability to bind DNA and to inhibit the effect of C/EBPalpha on CYP2C12 gene expression. Therefore, the ability of IRE-ABP to inhibit C/EBPalpha-stimulated CYP2C12 gene expression requires a functional DNA-binding domain. Taken together, our findings suggest that SRY-like proteins can bind to a subset of sequences recognized by the C/EBP family of DNA-binding proteins and modulate gene transcription in a context-specific manner.

3T3 Cells↗
PubMed1995

Expression of protein kinase C gene in the brain and heart of spontaneously hypertensive rats.

1. The aim of this study was to investigate protein kinase C (PKC) gene expression in spontaneously hypertensive rats (SHR). 2. Using the PKC oligodeoxyribonucleotide probes (gamma, epsilon), we detected PKC isoforms gene expression in the heart and brain of 4 and 20 week old SHR with those of age-matched Wistar-Kyoto (WKY) rats by northern blot analysis. 3. In the cerebral cortex, there were significantly increased levels of expression of the Ca2+-dependent isoform PKC-gamma in 4 and 20 weeks SHR compared with that of WKY, while Ca2+ -independent isoform PKC-epsilon did not differ between SHR and WKY. 4. In ventricular myocytes, there was a significant expression of the Ca2+-independent isoform PKC-epsilon in 4 and 20 week old SHR compared with that of WKY, while Ca2+ -dependent isoform PKC-gamma could not be detected in the same extracts of SHR or WKY. 5. We conclude that both of the Ca2+ -dependent and Ca2+ -independent PKC could be involved in the pathogenesis of SHR. Ca2+ -dependent PKC-gamma may be mainly involved in the modulation of blood pressure in the level of the central nervous system, while Ca2+ -independent PKC-epsilon could be related to the genetic myocardial hypertrophy.

Animals↗
PubMed1992

Expression of liver-specific member of the 3 beta-hydroxysteroid dehydrogenase family, an isoform possessing an almost exclusive 3-ketosteroid reductase activity.

We have recently characterized two types of rat 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase (3 beta-HSD) isoenzymes expressed in adrenals and gonads. In addition, we have cloned a third type of cDNA encoding a predicted type III 3 beta-HSD protein specifically expressed in the male rat liver which shares 80% similarity with the two other isoenzymes. Transient expression in human HeLa cells of the cDNAs reveals that the type III 3 beta-HSD protein does not display oxidative activity for the classical substrates of 3 beta-HSD, in contrast to the type I 3 beta-HSD isoenzyme. However, in the presence of NADH, type III isoenzyme, in common with the type I isoform, converts 5 alpha-androstane-3,17-dione (A-dione) and 5 alpha-dihydrotestosterone (DHT) to the corresponding 3 beta-hydroxysteroids. In fact, the type I and the type III isoenzymes have the same affinity for DHT with Km values of 5.05 and 6.16 microM, respectively. When NADPH is used as cofactor, the affinity for DHT of the type III isoform becomes higher than that of the type I isoform with Km values of 0.12 and 1.18 microM, respectively. The type III isoform is thus a 3-ketoreductase using NADPH as preferred cofactor which is responsible for the conversion of 3-keto-saturated steroids such as DHT and A-dione into less active steroids.

3-Hydroxysteroid Dehydrogenases↗
PubMed1992

Structure and tissue-specific expression of 3 beta-hydroxysteroid dehydrogenase/5-ene-4-ene isomerase genes in human and rat classical and peripheral steroidogenic tissues.

The enzyme 3 beta-hydroxysteroid dehydrogenase/5-ene-4-ene isomerase (3 beta-HSD) catalyzes the oxidation and isomerization of 5-ene-3 beta-hydroxypregnene and 5-ene-hydroxyandrostene steroid precursors into the corresponding 4-ene-ketosteroids necessary for the formation of all classes of steroid hormones. We have recently characterized two types of human 3 beta-HSD cDNA clones and the corresponding genes which encode deduced proteins of 371 and 372 amino acids, respectively, and share 93.5% homology. The human 3 beta-HSD genes containing 4 exons were assigned by in situ hybridization to the p11-p13 region of the short arm of chromosome 1. We have also recently elucidated the structure of three types of rat 3 beta-HSD cDNAs as well as that of one type of 3 beta-HSD from bovine and macaque ovary lambda gt11 cDNA libraries which all encode 372 amino acid proteins. The human type I 3 beta-HSD is the almost exclusive mRNA species detected in the placenta and skin, while the human type II is the predominant mRNA species in the adrenals, ovaries and testes. The predicted rat type I and type II 3 beta-HSD proteins expressed in adrenals, gonads and adipose tissue share 94% homology while they share 80% similarity with the liver-specific type III 3 beta-HSD. Transient expression of human type I and type II as well as rat type I and type II 3 beta-HSD cDNAs in HeLa human cervical carcinoma cells reveals that 3 beta-ol dehydrogenase and 5-ene-4-ene isomerase activities reside within a single protein and these cDNAs encode functional 3 beta-HSD proteins that are capable of converting 3 beta-hydroxy-5-ene-steroids into 3-keto-4-ene derivatives as well as the interconversion of 3 beta-hydroxy and 3-keto-5 alpha-androstane steroids. We have found that the rat type III mRNA species was below the detection limit in intact female liver while, following hypophysectomy, its accumulation increased to 55% of the levels measured in intact or HYPOX male rats, an increase which can be blocked by administration of ovine prolactin (oPRL). In addition, in female rats, treatment with oPRL for 10 days starting 15 days after HYPOX, markedly decreased ovarian 3 beta-HSD mRNA accumulation accompanied by a similar decrease in 3 beta-HSD activity and protein levels. Treatment with the gonadotropin hCG reversed the potent inhibitory effect of oPRL on these parameters and stimulated 3 beta-HSD mRNA levels in ovarian interstitial cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗
PubMed1991

Characterization of rat 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase cDNAs and differential tissue-specific expression of the corresponding mRNAs in steroidogenic and peripheral tissues.

The conversion of 3 beta-hydroxy-5-ene steroids by the enzyme complex 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase (3 beta-HSD) is an essential step in the biosynthesis of all classes of hormonal steroids. We report the characterization of two types of cDNA clones encoding rat 3 beta-HSD isolated from a rat ovary lambda gt11 cDNA library with a human 3 beta-HSD cDNA probe. Both type I and type II cDNAs encode proteins of 372 amino acids having 94% homology. Transient expression of the type I and the type II 3 beta-HSD cDNAs in HeLa human cervical carcinoma cells reveals that both proteins possess 3 beta-hydroxysteroid dehydrogenase as well as delta 5-delta 4 isomerase activities for both delta 5-pregnene and delta 5-androstene precursors, although the type I 3 beta-HSD protein is more active than the type II. RNA blot analysis using type I 3 beta-HSD cDNA identifies major mRNA transcripts of 1.7 kilobase in rat ovary, testis, and adrenal poly(A)+ RNA. RNase protection assay using type I- and type II-specific cRNA probes revealed the existence of the two corresponding mRNAs in male and female rat adrenals and gonads as well as in female adipose tissue while only type I mRNA is present in male and female kidney. Moreover, in situ hybridization performed using type-specific labeled 24-mer oligonucleotides confirms that type I is the major mRNA species in the ovary and further indicates that both mRNA species have a similar cellular distribution in the ovarian tissue with the highest level of expression found in corpora lutea. Immunoblot analysis using polyclonal antibodies raised against purified human placental 3 beta-HSD identified a single 42-kDa band in rat ovary, testis, and adrenal, which agrees with the calculated molecular masses of 41,911 and 42,150 daltons for the type I and II proteins, respectively. Determination of 3 beta-HSD enzymatic activity using [14C]pregnenolone and [14C]dehydroepiandrosterone as substrates shows that 3 beta-HSD activity is present not only in the gonads and adrenals of animals of both sexes, but also in many peripheral tissues including adipose tissue, mammary gland, kidney, liver, prostate, seminal vesicle, uterus, skin, brain, heart, thymus, pancreas, lung, and spleen. The present data indicate the existence of two mRNAs encoding rat 3 beta-HSD and their differential tissular distribution in both steroidogenic and peripheral tissues.(ABSTRACT TRUNCATED AT 400 WORDS)

Adipose Tissue↗
PubMed1991

Characterization of macaque 3 beta-hydroxy-5-ene steroid dehydrogenase/delta 5-delta 4 isomerase: structure and expression in steroidogenic and peripheral tissues in primate.

The conversion of 3 beta-hydroxy-5-ene steroids by the enzyme complex 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase (3 beta-HSD) is an obligatory step in the biosynthesis of all classes of hormonal steroids in classical steroidogenic as well as in peripheral tissues. To develop a model more closely related to the human, we have isolated and characterized cDNA clones encoding macaque 3 beta-HSD by screening a rhesus monkey ovary lambda gt11 cDNA library using a human 3 beta-HSD cDNA probe. Nucleotide sequence of 1629 bp from overlapping cDNA clones predicts a protein of 372 amino acids with a calculated molecular mass of 41,874 (excluding the first Met). The deduced amino acid sequence of macaque 3 beta-HSD displays 79.4% and 93.9% similarity with that of bovine and human 3 beta-HSD, respectively. RNA blot analysis performed under high stringency conditions of macaque poly(A)+ RNA samples using full-length 32P-labeled macaque 3 beta-HSD cDNA revealed the presence of an approximately 1.7 kb mRNA species in classical steroidogenic tissues, namely the ovary, testis and adrenal glands as well as in several peripheral tissues including the liver, kidney and epididymis. Computer analysis of the deduced macaque 3 beta-HSD protein sequence predicts the presence of an NH2-terminal membrane-associated segment as well as four additional membrane-spanning segments, thus suggesting that 3 beta-HSD is an integral protein. The availability of macaque cDNA should permit detailed studies concerning the tissue-specific expression as well as the hormonal regulation of 3 beta-HSD mRNA in classical steroidogenic glands as well as in peripheral tissues which are an important site of steroidogenesis in primates.

Adrenal Glands↗
PubMed1991

Structure and expression of a new complementary DNA encoding the almost exclusive 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4-isomerase in human adrenals and gonads.

The 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase (3 beta HSD) enzyme catalyzes the oxidation and isomerization of delta 5-3 beta-hydroxysteroid precursors into delta 4-ketosteroids, thus leading to the formation of all classes of steroid hormones. In addition, 3 beta HSD catalyzes the interconversion of 3 beta-hydroxy- and 3-keto-5 alpha-androstane steroids. Clinical observations in patients with 3 beta HSD deficiency as well as our recent data obtained by Southern blot analysis using a human placental 3 beta HSD cDNA (type I) as probe suggested the existence of multiple related 3 beta HSD isoenzymes. We now report the isolation and characterization of a second type of cDNA clone (arbitrarily designated type II) encoding 3 beta HSD after screening of a human adrenal lambda gt22A library. The nucleotide sequence of 1676 basepairs of human 3 beta HSD type II cDNA predicts a protein of 371 amino acids with a calculated molecular mass of 41,921 daltons, which displays 93.5% and 96.2% homology with human placental type I and rhesus macaque ovary 3 beta HSD deduced proteins, respectively. To characterize and compare the kinetic properties of the two isoenzymes, plasmids derived from pCMV and containing type I or type II 3 beta HSD full-length cDNA inserts were transiently expressed in HeLa human cervical carcinoma cells. In vitro incubation with NAD+ and 3H-labeled pregnenolone or dehydroepiandrosterone shows that the type I protein possesses a 3 beta HSD/delta 5-delta 4 isomerase activity higher than type II, with respective Km values of 0.24 vs. 1.2 microM for pregnenolone and 0.18 vs. 1.6 microM for dihydroepiandrosterone, while the specific activity of both types is equivalent. Moreover, incubation in the presence of NADH of homogenates from cells transfected with type I or type II 3 beta HSD indicates that dihydrotestosterone is converted into 5 alpha-androstane-3 beta, 17 beta-diol, with Km values of 0.26 and 2.7 microM, respectively. Ribonuclease protection assay using type I- and type II-specific cRNA probes revealed that type II transcripts are the almost exclusive 3 beta HSD mRNA species in the human adrenal gland, ovary, and testis, while type I transcripts correspond to the almost exclusive 3 beta HSD mRNA species in the placenta and skin and represent the predominantly expressed species in mammary gland tissue. The present data show for the first time that adrenals and gonads express a type of 3 beta HSD isoenzyme that is distinct from the type expressed in the placenta.(ABSTRACT TRUNCATED AT 400 WORDS)

Adrenal Glands↗
PubMed1990

Regulation of proopiomelanocortin messenger ribonucleic acid content by sex steroids in the arcuate nucleus of the female rat brain.

It has been recently demonstrated that sex steroids can negatively regulate beta-endorphin content as well as proopiomelanocortin (POMC) mRNA levels in the rat basal hypothalamus. In order to verify whether or not all the POMC neurons are equally affected by sex steroids, we arbitrarily divided the arcuate nucleus rostro-caudally into four equal portions and used an in situ hybridization technique to evaluate POMC gene expression in these different regions of the arcuate nucleus in the female rat. It was shown that ovariectomy induced an increase in mRNA levels in the most rostral region of the arcuate nucleus, an effect which was reversed by the concurrent administration of estradiol and dihydrotestosterone. On the other hand, estrogen administration to ovariectomized animals produced a marked depression of mRNA levels in all the regions of the arcuate nucleus with the exception of the most caudal one. These results suggest that sex steroids exert their action in subpopulations of POMC neurons.

Animals↗
PubMed1990

Synthetic progestins stimulate prostatic binding protein messenger RNAs in the rat ventral prostate.

In order to assess the intrinsic androgenic activity of the synthetic progestins currently used as antiandrogens for the treatment of prostate cancer and other androgen-sensitive diseases, cyproterone acetate (CPA), medroxyprogesterone acetate (MPA) and megestrol acetate (MEG) were administered for 4 days to adult rats castrated 4 days previously. The effects of these compounds were measured on highly specific and sensitive markers of androgen action in the rat ventral prostate, namely the levels of messenger RNAs encoding the C1 (PBP-C1) and C3 (PBP-C3) components of rat prostatic binding protein (PBP). Steady-state mRNA levels were measured by dot-blot hybridization as well as by in situ hybridization. Treatment with CPA or MEG, at the twice daily dose of 10 mg, caused respective 2- and 4.5-fold increases in the steady-state levels of mRNA encoding PBP-C1. MPA, at the dose of 0.45 mg, twice daily, was approximately 40 times as potent as MEG, leading to an 8-fold increase in PBP-C1 mRNA levels. While the pure nonsteroidal antiandrogen flutamide (10 mg, twice daily) did not cause accumulation of PBP mRNAs when administered to castrated rats, it completely reversed the stimulatory effects of the synthetic progestins CPA, MPA and MEG. The results obtained by in situ hybridization were similar to those obtained by dot-blot analysis. Moreover, the synthetic progestins caused similar androgenic effects on PBP-C3 mRNA levels. The present data indicate that all three synthetic progestins currently used for the treatment of prostate cancer possess significant intrinsic androgenic activity as evidenced by their stimulatory effects on the accumulation of mRNAs sensitive to androgen action. Consequently, as indicated by this sensitive and androgen-specific in vivo rat model, such compounds are not recommended for the treatment of conditions requiring an optimal blockade of androgens, especially prostate cancer.

Androgen-Binding Protein↗
PubMed1990

Interactions between estrogens, androgens, progestins, and glucocorticoids in ZR-75-1 human breast cancer cells.

The human breast cancer cell line ZR-75-1 possesses androgen, estrogen, progesterone, and glucocorticoid receptors, thus offering a good model to study the specific role of each class of steroids in the control of breast cancer growth. Although the stimulatory action of classical estrogens (E2 and estrone) is well known, we have found a potent mitogenic effect of the adrenal estrogen androst-5-ene-3 beta,17 beta-diol (delta 5-diol) at concentrations within the range of those found in the serum of adult women, thus suggesting that delta 5-diol might be the most important estrogen in women. Androgens, on the other hand, exert a potent inhibitory effect on basal ZR-75-1 cell growth and completely reverse the stimulatory effect of estrogens on the same parameter. The antiproliferative effect of androgens was completely prevented by the antiandrogen OH-FLU, thus suggesting an action mediated by the androgen receptor. Part of the effect of androgens can be explained by the marked inhibition of estrogen receptor binding and mRNA levels by androgens. The antiproliferative effect of androgens is additive to that exerted by antiestrogens. Progestins, on the other hand, exert a specific antiproliferative effect in the presence of estrogens, the effect of progestins being antagonized by the stimulatory action of insulin on cell growth. Medroxyprogesterone acetate (MPA), a compound frequently used in the treatment of breast cancer in women, exerts its main inhibitory action through an androgen receptor-mediated action, whereas its glucocorticoid-like activity could play an additional role at high concentrations. All four classes of steroids are present, to various extents, as lipophilic esters of long-chain fatty acids. It is of interest to mention that all steroids that inhibit ZR-75-1 breast cancer cell growth (androgens, progestins, and glucocorticoids) stimulate the secretion and mRNA levels of gross cystic disease fluid protein-15 (GCDFP-15), whereas estrogens have the opposite effects, thus suggesting that GCDFP-15 could well be a good marker for monitoring the response to androgens, progestins, and antiestrogens during the course of breast cancer therapy.

Androgens↗