Clinical associations of the genetic variants of CTLA-4, Tg, TSHR, PTPN22, PTPN12 and FCRL3 in patients with Graves' disease

OBJECTIVE

Graves' disease (GD) is an organ-specific autoimmune disorder. Both immune-modulating genes and thyroid-specific genes are involved in its genetic pathogenesis. It remains unclear, however, how the interactions of various susceptibility genes contribute to the pathogenesis and clinical severity of the disease. The purpose of this study was to investigate the relationships between GD and single nucleotide polymorphisms (SNPs) from CTLA-4, PTPN22, PTPN12, FCRL3 (general autoimmunity genes regulating T and B cells) and the TSHR and Tg genes (disease-specific genes). Furthermore, we evaluated the influences these SNPs have on the risk and severity of GD.

DESIGN AND METHODS

This cross-sectional clinical study was performed in 436 GD patients and 316 healthy, gender-matched individuals. Twenty-eight SNPs from CTLA-4, PTPN22, PTPN12, FCRL3, TSHR and Tg genes were genotyped and their associations with the risk and severity of GD were analysed.

RESULTS

The CTLA-4 rs231779, Tg rs2069550 and PTPN22 rs3789604 SNPs were associated with GD, with additive risk effects present in rs231779 and rs2069550. The ACACC and ACGCT haplotypes, composed of five SNPs in the CTLA-4 gene (rs4553808, rs5472909, rs231775, rs231777 and rs231779), were protective and risk haplotypes respectively. The AA genotype of PTPN22 rs3789604 and AA genotype of FCRL3 rs7528684 were correlated with a reduced risk of GD, while the CC genotype of TSHR rs2239610 was associated with higher serum concentrations of FT4 and TRAb. Logistic analysis confirmed the contribution of CTLA-4 rs231779 to the development of GD.

CONCLUSIONS

These preliminary results demonstrate that the immune-regulatory gene CTLA-4 and the thyroid-specific gene Tg contribute to the risk of Graves' disease with additive effects, while PTPN22 rs3789604 and FCRL3 rs7528684 polymorphisms are protective against the disease. In addition, the TSHR rs2239610 SNP is related to the severity of Graves' disease.

[Genotype analysis of killer cell immunoglobulin-like receptors in Graves' disease patients]

AIM

Killer cell immunoglobulin-like receptor (KIR) can modulate the activity of NK and T lymphocyte. To investigate whether the KIR genotype possessing a susceptibility to Graves disease (GD).

METHODS

Using PCR-SSP to detect KIR genotype in 96 GD patients and 96 randomly selected healthy controls.

RESULTS

The genotype frequency of 2DS2-, 2DL2-, 2DL3+, 2DL1+, 3DL1+, 3DS1-, 2DL5-, 2DS3-, 2DS5-, 2DS1-, 2DS4- was significantly higher in the patient group compared to that of the control group (6.25% vs 0%, P<0.05). Genotype of 2DS2-, 2DL2-, 2DL3+, 2DL1+, 3DL1+, 3DS1-, 2DL5-, 2DS3-, 2DS5-, 2DS1-, 2DS4+ is the most prevalent in the controls (28.13% vs 10.42%, P<0.01). Genotypes without activating KIR genes have higher frequency in patient group.

CONCLUSION

The difference of KIR genotypes between GD patients and healthy controls may explain the pathogenesis of GD.

[Overexpression of angiotensin converting enzyme 2 inhibits inflammatory response of atherosclerotic plaques in hypercholesterolemic rabbits]

OBJECTIVE

Angiotensin converting enzyme 2 (ACE2) efficiently hydrolyses the potent vasoconstrictor angiotensin II to vasodilative angiotensin (1-7). We hypothesized that ACE2 overexpression may inhibit inflammation response in atherosclerotic plaque by degrading Ang II into Ang-(1-7).

METHODS

Atherosclerosis (AS) plaques were induced in the abdominal aorta of 38 rabbits by endothelial injury and atherogenic diet for 3 months. Rabbits were then underwent injection of a recombinant adenovirus (2.5 x 10(9) pfu/ml) carrying a murine ACE2 gene (Ad-ACE2) through a catheter into the abdominal aortic segments rich in plaques (n = 19) or injection of a control vector Ad-EGFP (n = 19). One month later, all rabbits were sacrificed and plaques from aortic segments were analyzed.

RESULTS

ACE2 expression in aortic tissues of the Ad-ACE2 group were confirmed by immunohistochemistry. Macrophage infiltration (13.6% +/- 4.2% vs. 23.6% +/- 6.9%, P < 0.01) and MCP-1 expression (13.2% +/- 0.4% vs. 25.0% +/- 7.4%, P < 0.01) were significantly reduced in Ad-ACE2 group compared to Ad-EGFP group.

CONCLUSIONS

Overexpression of ACE2 inhibited atherosclerotic plaque inflammation response in hypercholesterolemic rabbits.

[Preliminary functional analysis of a novel mutation in GATA-4 gene in Chinese patients with congenital cardiac septal defects]

OBJECTIVE

To perform the functional analysis of a novel H436Y mutation of GATA-4 gene identified in Han Chinese patients with congenital cardiac septal defects.

METHODS

Using bioinformatics to predict if the H436Y mutation in the GATA-4 gene affects its protein function. H436Y mutation in the GATA-4 gene was generated by Quick Change Lightning site-directed mutagenesis kit and verified by DNA sequencing. GATA-4-wt or GATA-4-mut DNA was cotransfected into Hela cells with DNA for the luciferase reporter gene atrial natriuretic factor (ANF), and luciferase activity was measured by an LKB luminometer 48 h after transient transfection.

RESULTS

Alignment of the GATA-4 amino acid sequence indicated that the histidine residue at position 436 was conserved, and H436Y mutation in the GATA-4 gene is expected to affect its protein function. The H436Y mutation significantly reduced the transcriptional activation of downstream reporter ANF when compared to wild-type GATA-4 (P<0.01).

CONCLUSION

The mutation c.1306C-->T of the GATA-4 gene impaired the activation of the downstream target, suggesting that the H436Y mutation in the C-terminal region of the GATA-4 gene might prevent its biological function.

[Clinical and molecular genetic analysis for 7 patients from 5 pedigrees with 17a-hydroxylase/17, 20 lyase deficiency]

OBJECTIVE

To investigate the clinical and genetic characteristics of 7 patients from 5 families with 17a-hydroxylase/17,20 lyase deficiency (17OHD) and the CYP17A1 mutation in Chinese.

METHODS

Clinical features and laboratory data were collected from 5 families with 17OHD. PCR direct sequencing was performed to screen the mutation of CYP17A1 gene of the patients. Polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP) and sequencing were performed to screen the mutations of CYP17A1 gene in 288 healthy individuals from Shandong province.

RESULTS

Seven patients (5 of them were 46,XX; 2 were 46,XY) had typical clinical presentation of sexual infantilism, hypertension and hypokalemia. Hormone profile indicated decreased plasma cortisol and sex hormones, and elevated blood adrenocorticotrophic hormone (ACTH). TAC329AA and H373L in exon 6 and D487_F489del in exon 8 were identified from the patients. One heterozygote for D487_F489del was identified in 288 healthy controls.

CONCLUSION

The TAC329AA and D487_F489del of the CYP17A1 gene were the most frequent mutations in Chinese with 17OHD.There might be certain frequency of heterozygotes for D487_F489del in Chinese population.

[Association between GATA-4 mutations and congenital cardiac septal defects in Han Chinese patients]

OBJECTIVE

To elucidate the association between GATA-4 gene mutations and congenital cardiac septal defects in Han Chinese patients.

METHODS

Fifty Han Chinese patients with congenital cardiac septal defects and 100 normal subjects with the same ethnical background were studied. Total six exons and the intron-exon boundaries of GATA-4 were amplified by the polymerase chain reaction. The polymerase chain reaction products were purified and directly sequenced with automatic sequencer.

RESULTS

Two novel heterozygous mutations were discovered in the GATA-4 gene of patients with congenital cardiac septal defects, His28Tyr in exon 2 and His436Tyr in exon 7 respectively, which were absent in the control population and not reported in the SNP database (http://www.ncbi.nlm.nih.gov/SNP).

CONCLUSION

Our finding suggests that the mutations in the transcription factor GATA-4 may be related to congenital cardiac septal defects in Han Chinese patients.

C-reactive protein inhibits adiponectin gene expression and secretion in 3T3-L1 adipocytes

C-reactive protein (CRP) is considered as one of the most sensitive markers of inflammation. The aim of the present study is to investigate the effects of CRP on the production of adiponectin in 3T3-L1 adipocytes. Northern and western blot analysis revealed that CRP treatment inhibited adiponectin mRNA expression and secretion in a dose- and time-dependent manner. Co-incubation of adipocytes with rosiglitazone and CRP decreased induction of adiponectin gene expression by rosiglitazone. However, luciferase reporter assays did not show that CRP affected the activity of approximately 2.1 kb adiponectin gene promoter, which was increased by rosiglitazone alone. Pharmacological inhibition of phosphatidylinositol (PI)-3 kinase by LY294002 partially reversed inhibition of adiponectin gene expression by CRP. These results collectively suggest that CRP suppresses adiponectin gene expression partially through the PI-3 kinase pathway, and that decreased production of adiponectin might represent a mechanism by which CRP regulates insulin sensitivity.

Genetic diagnosis of multiple affected tissues in a patient with McCune-Albright syndrome

McCune-Albright syndrome (MAS) is a sporadic disorder characterized by the classic triad of polyostotic fibrous dysplasia, café-au-lait' skin pigmentation, and hyperfunctional endocrinopathy. It is caused by embryonic somatic mutations leading to the substitution of His or Cys for Arg at amino acid 201 of the alpha-subunit of the signal transduction protein Gs (Gsalpha). A 32-year-old man was diagnosed as McCune-Albright syndrome with the following findings: polyostotic fibrous dysplasia, café-au-lait' spots and acromegaly. An ultrasonic examination showed that he had left-pleural effusion, which disappeared after almost a year without special treatment. Genomic DNA was isolated from the peripheral blood, bone tissue, skin lesion and pleura samples of the patient. Then PCR and direct sequencing were performed. An activating mutation of the Gsalpha gene (Arg201Cys) was found in the genomic DNA isolated from the peripheral blood and the bone tissue, but not in genomic DNA isolated from the skin and pleura samples.

Gene expression profiling in human null cell pituitary adenoma tissue

It is estimated that up to one in five individuals develops pituitary gland tumors, despite the common occurrence of these tumors, the pathogenetic mechanisms underlying their development mainly remain unknown. We studied the gene expression in null cell adenomas compared with normal pituitary by expressed sequence tags (EST) sequencing and cDNA microarray on large scale. Both approaches of EST sequencing and microarray analysis showed that 17 genes were differentially expressed in human null cell pituitary adenoma tissues, among which 14 genes were overexpressed and three genes were underpressed. Five of the genes with potential oncogenic significance by RT-real time quantitative PCR. Synaptotagmin (SYT) are integral membrane proteins of synaptic vesicles considered to serve as Ca(2+) sensors in the process of vesicular trafficking and exocytosis. Calcium binding to participates in triggering neurotransmitter release at the synapse. In view of our finding that SYT is overexpressed in null cell adenomas, these tumors may be capable of secreting some unknown hormones or peptides. ATP5B and MDH1 were involved in the energy metabolism, whose overexpression in null cell adenomas provide us with a new perspective of exploring the oncogenesis of these tumors. All of these data may contribute to the understanding of null cell adenoma formation and development.

Streptococcal toxic shock syndrome caused by Streptococcus suis serotype 2

BACKGROUND

Streptococcus suis serotype 2 (S. suis 2, SS2) is a major zoonotic pathogen that causes only sporadic cases of meningitis and sepsis in humans. Most if not all cases of Streptococcal toxic shock syndrome (STSS) that have been well-documented to date were associated with the non-SS2 group A streptococcus (GAS). However, a recent large-scale outbreak of SS2 in Sichuan Province, China, appeared to be caused by more invasive deep-tissue infection with STSS, characterized by acute high fever, vascular collapse, hypotension, shock, and multiple organ failure.

METHODS AND FINDINGS

We investigated this outbreak of SS2 infections in both human and pigs, which took place from July to August, 2005, through clinical observation and laboratory experiments. Clinical and pathological characterization of the human patients revealed the hallmarks of typical STSS, which to date had only been associated with GAS infection. Retrospectively, we found that this outbreak was very similar to an earlier outbreak in Jiangsu Province, China, in 1998. We isolated and analyzed 37 bacterial strains from human specimens and eight from pig specimens of the recent outbreak, as well as three human isolates and two pig isolates from the 1998 outbreak we had kept in our laboratory. The bacterial isolates were examined using light microscopy observation, pig infection experiments, multiplex-PCR assay, as well as restriction fragment length polymorphisms (RFLP) and multiple sequence alignment analyses. Multiple lines of evidence confirmed that highly virulent strains of SS2 were the causative agents of both outbreaks.

CONCLUSIONS

We report, to our knowledge for the first time, two outbreaks of STSS caused by SS2, a non-GAS streptococcus. The 2005 outbreak was associated with 38 deaths out of 204 documented human cases; the 1998 outbreak with 14 deaths out of 25 reported human cases. Most of the fatal cases were characterized by STSS; some of them by meningitis or severe septicemia. The molecular mechanisms underlying these human STSS outbreaks in human beings remain unclear and an objective for further study.

[Study of the impact of candidate genes on bone mineral density in postmenopausal women]

OBJECTIVE

To investigate the impact of multiple candidate genes on bone mineral density in postmenopausal women.

METHODS

Bone mineral density (BMD) at lumbar spine and femoral neck were measured by dual-energy X-ray absorptiometry (DEXA) in 205 postmenopausal women. Polymerase chain reaction (PCR) and direct sequencing technique were used to identify osteoprotegerin gene polymorphism. Parathyroid hormone, calcitonin receptor, osteocalcin and leptin receptor genes were evaluated through PCR and restriction fragment length polymorphism. Leptin gene was genotyped by PCR and agarose electrophoresis.

RESULTS

One G-1181C single nucleotide polymorphism was found in the first exon of the osteoprotegerin gene. After adjustment for age and body mass index, women who were with the CC genotype of osteoprotegerin gene or the bb genotype of parathyroid hormone gene had the highest BMD value at the lumbar spine, which was (1.042 +/- 0.142) g/cm(2) and (1.196 +/- 0.133) g/cm(2), respectively. No association was found among calcitonin receptor, osteocalcin, leptin and leptin receptor genes with BMD in postmenopausal women. Multivariate regression analysis found that the osteoprotegerin, parathyroid hormone and osteocalcin genes associated with the variance of BMD at the lumbar spine, and the parathyroid gene associated with the variance of BMD at the femoral neck.

CONCLUSIONS

There is some association between osteoprotegerin, parathyroid hormone genes and BMD in postmenopausal women. However, no relationship has been found among calcitonin receptor, osteocalcin, leptin and leptin receptor genes with BMD in postmenopausal women. The osteoprotegerin gene may be the useful genetic marker for osteopenia in postmenopausal women.

Slit-like 2, a novel zebrafish slit homologue that might involve in zebrafish central neural and vascular morphogenesis

Nervous and vascular systems grow as parallel networks, indicating common cues in distal targets. We have identified a novel zebrafish gene slit-like 2 (slitl2) that might involve in zebrafish central neural and vascular morphogenesis. Whole-mount in situ hybridization of zebrafish embryo detected distinct signals of slitl2 transcripts in zebrafish midline structure of central nervous system similar to that of slits. Strong expression is also observed in zebrafish vasculature. Zebrafish slitl2 shares amino acid sequence identity of 41% with Homo sapiens slitl2 (vasorin) and Mus musculus slitl2, and 35%, 33% with Danio rerio slit3, slit2. Analysis of zebrafish slitl2 cripto growth factor domain, extracellular matrix protein slit domain, and putative signal peptide confirms that as a secreted and cell-surface protein slitl2 may be essential in axon guidance, vessel development, and axis patterning. These results provide evidence that slitl2 may play important roles in zebrafish central nervous system and vascular morphogenesis.

Expression of feeding-related peptide receptors mRNA in GT1-7 cell line and roles of leptin and orexins in control of GnRH secretion

AIM

To investigate the expression of feeding-related peptide receptors mRNA in GT1-7 cell line and roles of leptin and orexins in the control of GnRH secretion.

METHODS

Receptors of bombesin3, cholecystokinin (CCK)-A, CCK-B, glucagon-like peptide (GLP)1, melanin-concentrating hormone (MCH)1, orexin1, orexin2, neuromedin-B, neuropeptide Y (NPY)1 and NPY5, neurotensin (NT)1, NT2, NT3, and leptin receptor long form mRNA in GT1-7 cells were detected by reversed transcriptase-polymerase chain reaction. GT1-7 cells were treated with leptin, orexin A and orexin B at a cohort of concentrations for different lengths of time, and GnRH in medium was determined by radioimmunoassay (RIA).

RESULTS

Receptors of bombesin 3, CCK-B, GLP1, MCH1, orexin1, neuromedin-B, NPY1, NPY5, NT1, NT3, and leptin receptor long form mRNA were expressed in GT1-7 cells, of which, receptors of GLP1, neuromedin-B, NPY1, and NT3 were highly expressed. No amplified fragments of orexin2, NT2, and CCK-A receptor cDNA were generated with GT1-7 RNA, indicating that the GT1-7 cells did not express mRNA of them. Leptin induced a significant stimulation of GnRH release, the results being most significant at 0.1 nmol/L for 15 min. In contrast to other studies in hypothalamic explants, neither orexin A nor orexin B affected basal GnRH secretion over a wide range of concentrations ranging from 1 nmol/L to 500 nmol/Lat 15, 30, and 60 min.

CONCLUSION

Feeding and reproductive function are closely linked. Many orexigenic and anorexigenic signals may control feeding behavior as well as alter GnRH secretion through their receptors on GnRH neurons.

[Clinical and molecular research in a case of familial Carney complex]

OBJECTIVE

A case of primary pigmented nodular adrenal disease (PPNAD) was first diagnosed in Ruijin Hospital, Shanghai, China and molecular genetic research was then carried on the proband and his family members.

METHODS

History and laboratory tests were routinely taken. Liddle's test, adrenal CT and pituitary magnetic resonance imaging were also carried out. Complete family history was obtained and eight of the family members donated their blood for DNA extraction. Polymerase chain reaction was done on all the exons of PRKAR1A gene and the product of the reaction was sequenced with ABI 3700. The right adrenal of the patient was then resected, part of the tissue was preserved in liquid nitrogen for DNA/RNA extraction and the remaining sent to Department of Pathology.

RESULTS

The patient presented an atypical appearance of Cushing's syndrome. His father had a typical history of cardiac myoma. Cortisone level could not be refrained in Liddle's test for the patient. Imaging examination presented a nodular adrenal and a full pituitary. A novel mutation of PRKAR1A-S147N was found in both the patient's and his father's gene.

CONCLUSIONS

This is the first patient diagnosed as PPNAD based on his clinical manifestations, laboratory tests and imaging and pathological examinations. According to the history of his father and the results of molecular genetic analysis, the diagnosis of Carney complex can be established on this patient and his father. It is also the first time that this kind of point mutation was found in Chinese people.

[Indentification of differentially expressed genes in proliferating and involuting hemangiomas by cDAN microarray analysis of gene-expression profiles]

OBJECTIVE

To investigate the differentially expressed genes of proliferating and involuting hemangiomas by cDNA microarray analysis of gene-expression profiles in an effort to identify the key disease-related genes.

METHODS

Samples were processed from total RNA and purified to mRNA, which was reverse-transcripted and hybridized onto Biodoor Genechip expression microarrays. Analyses were performed to determine the consensus pattern of gene expression in the proliferating and involuting stages of the same hemangioma and the changes in the expression level.

RESULTS

In proliferating hemangioma, 79 genes were overexpressed, and 115 genes were underexpressed in comparison with the involuting hemangioma. Some cytokines and growth factors such as neurotensin, Nov, CYR6, keratinocyte growth factor, interleukin-10 were overexpressed in proliferative hemangioma. In involuting hemangioma, apoptotic factors such as bcl-2 binding component, cytochrome C were overexpressed. The overexpression of Nov, CYR6, c-myc implied that angiogenesis and oncogenes might participate in the pathogenesis of hemangiomas. Mitochondria activated apoptotic passage (cytokines, bcl-2, cytochrome C) and Wnt/beta-catenin passage(Frizzled, beta-catenin, c-myc) were involved.

CONCLUSION

The development of hemangiomas may be the results of imbalance of cell proliferation and apoptosis.

[Study on the genome structure of human telomeric repeat binding factor 1 and its pseudogenes]

OBJECTIVE

To determine the genome structure of human telomeric repeat binding factor 1 (TERF1) and its pseudogenes.

METHODS

Sequences were obtained from GenBank and analyzed using the BLAST program and other relevant biology program (Sequencher, DNA Strider and Autoassembler, etc) to determine the genome and pseudogenome structure of TERF1. PCR and sequencing were performed to verify the results.

RESULT

TERF1 gene which mapped to 8q13 was divided into 10 exons. It had four processed pseudogenes located on chromosome 13, 18, 21 and X respectively (Psi TERF1-13 Psi TERF1-18 Psi TERF1-21 and Psi TERF1-X ). They were entire intronless TERF1 genes which lacked some exons. Three homologous fragments of at least 60 kb on the flanking region of Psi TERF1-13, Psi TERF1-18 and Psi TERF1-21, respectively were noted.

CONCLUSION

TERF1 gene has 10 exons. It has four processed pseudogenes which are located on chromosome 13, 18, 21, and X, respectively. Large homologous fragments that belong to the recently duplicated segments are transchromosomal duplications.

[Effect of berberine on the differentiation of adipocyte]

OBJECTIVE

To observe the effect of berberine on the differentiation of 3T3-L1 preadipocytes into adipocytes and to elucidate its mechanism.

METHODS

3T3-L1 preadipocytes were cultured and then divided into 7 groups into whose media were added berberine of the concentrations of 0, 0.1, 1, 10, and 100 micro mol/L, 100 nmol/Linsulin, and 10 micro mol/L berberine + 100 nmol/L insulin. The proliferation of 3T3-L1 preadipocytes was detected by MTT method. The accumulation of lipid in the cytoplasm of differentiated adipocytes was observed by oil red O staining. The peroxisome proliferation activated receptor gamma2 (PPARgamma2) mRNA and protein were detected by RT-PCR and Western blotting respectively.

RESULTS

MTT method showed that the absorbance at 570 nm of 3T3-L1 preadipocytes increased by 17% (P < 0.01), 36% (P < 0.001), and 22% (P < 0.05) in the groups of 1, 10, and 100 micro mol/L berberine, by 53% (P < 0.0001)in the group of 100 nmol/L insulin, and by 66% in the group of 10 micro mol/L berberine + 100 nmol/L insulin. There were less and smaller lipid droplets in the 3T3-L1 adipocytes treated with berberine as compared with the untreated control cells and only 10% - 20% of the treated cells displayed big lipid drops. RT-PCR showed that berberine significantly reduced the expression of PPARgamma2 mRNA by 48% (P < 0.01) in the course of 3T3-L1 adipocyte differentiation. Western blotting showed that berberine inhibited the expression of PPARgamma2 protein.

CONCLUSION

Berberine promotes the proliferation of 3T3-L1 preadipocytes, decreases the accumulation of lipid drops therein, and inhibits the terminal differentiation of adipocyte, which may be associated with its effect on decreasing the expression of PPARgamma2 mRNA and protein, suggesting that berberine has advantages in the treatment of obesity patients with type 2 diabetes.

[A case report and pedigree study of a single point mutation in RET proto-oncogene and type 2B multiple endocrine neoplasia]

OBJECTIVE

To determine the relationship between a single point mutation in RET proto-oncogene and the occurrence of multiple endocrine neoplasia type 2B (MEN-2B) in a Chinese pedigree.

METHODS

We used the methods of polymerase chain reaction (PCR), reverse transcriptase polymerase chain reaction (RT-PCR) and direct gene sequencing of PCR products by an automated DNA sequencer to scan the entire exon 16 of RET proto-oncogene in the tumor (c)DNA from one patient with MEN-2B and the leukocyte DNA from this patient and both of his parents.

RESULTS

We found the same mutation Met(ATG)-->Thr(ACG) at codon 918 in exon 16 of RET proto-oncogene in both the tumor (c)DNA and leukocyte DNA of the MEN-2B patient in the form of homozygous missense mutation, but there was no corresponding mutation in leukocytes DNA of his parents.

CONCLUSION

We propose that in Chinese population, the point mutation M918T is also associated with the onset of MEN-2B and this case of MEN-2B is sporadic. Thus it may provide a genetic basis for the early diagnosis and treatment of patients suffering from MEN-2B and their at-risk family members in Chinese population.

[Novel full-length cDNA cloning from normal adrenal gland and pheochromocytoma and functional prediction]

OBJECTIVE

To investigate methodology of cloning full-length cDNA from tissues of normal adrenal gland and pheochromocytoma and predict their function.

METHODS

104 samples from normal adrenal gland and 22 samples from pheochromocytoma were examined by expressed sequence tags (EST) sequencing, bioinformatics analysis, in silico cloning, rapid amplification of cDNA ends and RT-PCR.

RESULTS

Among the 126 samples of novel full-length cDNA cloning 104 were from normal adrenal gland, and 22 from pheochromocytoma (PC). Among the novel genes 50 were cloned by direct sequencing of clones, 74 by in silico cloning, and 2 by rapid amplification of cDNA ends, and the localization of chromosomes was made with UniGene searching and radiation hybrid (RH) procedure. Comparison of homology and analysis of motif or domain showed that some genes may be important functional genes, such as those coding signaling proteins, proteins associated with ion channel, enzymes involved in hormone production, important transcription factors, translation initiation factors, etc. 7 of the novel full-length cDNAs are new isoforms produced by alternative splicing.

CONCLUSION

126 novel full-length cDNAs have been cloned from adrenal tissues by large-scale EST sequencing and bioinformatic tools in a rather short time, some of which may play an important role in regulating adrenal functions and tumorigenesis of adrenal gland.

Gene expression profiling in the human hypothalamus-pituitary-adrenal axis and full-length cDNA cloning

The primary neuroendocrine interface, hypothalamus and pituitary, together with adrenals, constitute the major axis responsible for the maintenance of homeostasis and the response to the perturbations in the environment. The gene expression profiling in the human hypothalamus-pituitary-adrenal axis was catalogued by generating a large amount of expressed sequence tags (ESTs), followed by bioinformatics analysis (http://www.chgc.sh.cn/ database). Totally, 25,973 sequences of good quality were obtained from 31,130 clones (83.4%) from cDNA libraries of the hypothalamus, pituitary, and adrenal glands. After eliminating 5,347 sequences corresponding to repetitive elements and mtDNA, 20,626 ESTs could be assembled into 9, 175 clusters (3,979, 3,074, and 4,116 clusters in hypothalamus, pituitary, and adrenal glands, respectively) when overlapping ESTs were integrated. Of these clusters, 2,777 (30.3%) corresponded to known genes, 4,165 (44.8%) to dbESTs, and 2,233 (24.3%) to novel ESTs. The gene expression profiles reflected well the functional characteristics of the three levels in the hypothalamus-pituitary-adrenal axis, because most of the 20 genes with highest expression showed statistical difference in terms of tissue distribution, including a group of tissue-specific functional markers. Meanwhile, some findings were made with regard to the physiology of the axis, and 200 full-length cDNAs of novel genes were cloned and sequenced. All of these data may contribute to the understanding of the neuroendocrine regulation of human life.