PubMed Health⌕ Search

Biomedical subjects

Sudha Rao

Publications and source records attributed to Sudha Rao.

13 recordsLinked to original sources
PubMed2007

Regulation of mouse Heparanase gene expression in T lymphocytes and tumor cells.

Heparanase (HPSE) is an endoglycosidase that cleaves heparan sulfate (HS) and plays an important role in tumor metastasis, angiogenesis and inflammation. The regulation of HPSE expression and function is tightly controlled and the increasing use of the mouse as an animal model to define the role of HPSE in many physiological and pathological settings, makes understanding the regulatory mechanisms of HPSE in this species of fundamental importance. However, the expression distribution of the mouse Hpse gene and the mechanisms that regulate its transcription are poorly defined. In this study, the mouse Hpse gene was determined to encode for two mRNA transcripts of 1.9 and 3.2 kb in length with identical open reading frames that showed similar tissue expression distribution to the human HPSE. The mouse Hpse promoter was cloned and a 478-bp minimal promoter was identified that contained regulatory elements responsible for both basal promoter activity in mouse tumor cells as well as inducible activity in T cells. Mutagenesis and transactivation studies identified a functional site in the minimal promoter region for the transcription factor Early growth response gene 1 (Egr1). Interestingly, Egr1 acted differentially in mouse tumor cells, functioning in an activating or repressive manner in breast carcinoma or melanoma cells, respectively. Furthermore, the proximal region of the promoter, identified as important in the regulation of Hpse transcription, was shown to become accessible in T cells upon cell activation. Significantly, the maximal accessibility of the promoter occurred at 16 h post-stimulation, which correlated with the induction kinetics of Hpse mRNA expression. In summary, this study demonstrates that mouse Hpse is expressed and regulated in a similar manner to human HPSE and also provides some novel insights into mechanisms of Hpse gene regulation that are likely to be relevant to control of the human gene.

Animals↗
PubMed2006

Etiology and clinical profile of ambiguous genitalia an overview of 10 years experience.

One hundred nine patients presenting with ambiguous genitalia over the past 10 years (year 1995 to 2004) to Pediatric Endocrine Service of our hospital were reviewed. On the basis of clinical and investigative evaluation like hormonal and biochemical estimations, imaging studies, karyotype and invasive techniques like genitoscopy, laproscopy, open exploration and biopsy of gonads when indicated, these cases could be categorised as Genetic females with virilisation or FPH (n = 30 cases, 27.5 % Genetic males undervirilised or MPH (n = 57 cases, 52.3 %), Disorders of gonadal differentiation (n = 11, 10.1 %) Nine patients with gonadal dysgenesis and 2 with true hermaphroditism and the syndromic form of ambiguous genitalia (n = 2, 1.8 %). Congenital adrenal hyperplasia (CAH) was the underlying cause in all cases of FPH, the salt wasting form in 23/30 and simple virilising form in 7. Major categories in MPH group were Androgen insensitivity syndrome in 28 % (16/57) and 5a reductase deficiency in 23% (13/57).

Adrenal Hyperplasia, Congenital↗
PubMed2006

Polyglandular autoimmune syndrome-type I.

Polyglandular autoimmune syndrome type I is a rare disorder characterized by mucocutaneous candidiasis (MC), hypoparathyroidism (HP) and adrenal insufficiency , requiring regular follow up as the components of the syndrome appear at different age groups. We report a six and half year boy having this syndrome and presenting with MC, HP and ectodermal dystrophy.

Candidiasis, Chronic Mucocutaneous↗
PubMed2005

Early growth response gene 1 (EGR1) regulates heparanase gene transcription in tumor cells.

Heparanase is an endoglycosidase that degrades heparan sulfate chains of heparan sulfate proteoglycans, a key component of extracellular matrix and basement membranes. Studies using heparanase inhibitors and gene silencing have provided evidence to support an important role for heparanase in tumor metastasis and angiogenesis. The expression of heparanase is normally very tightly controlled, however, it is commonly deregulated in tumor cells, which express elevated heparanase activity that correlates with high levels of heparanase mRNA. We recently identified the transcription factor early growth response gene 1, EGR1, as a key regulator of inducible heparanase transcription in T cells. In this study using chromatin immunoprecipitation, we demonstrate for the first time that EGR1 binds to the heparanase gene promoter in vivo. The important question of the role of EGR1 in regulating heparanase transcription in tumor cells was then assessed. Studies were carried out in four epithelial tumor lines of different tissue origin. Functional dissection of the heparanase promoter identified a 280-bp region that was critical for transcription of the heparanase gene. Transactivation studies using an EGR1 expression vector co-transfected with a reporter construct containing the 280-bp region showed EGR1-activated heparanase promoter activity in a dose-dependent manner in prostate or breast adenocarcinoma and colon carcinoma cell lines. In contrast, overexpression of EGR1 resulted in a dose-dependent repression of promoter activity in melanoma cells. Using site-directed mutagenesis the 280-bp region was found to contain two functional EGR1 sites and electrophoretic mobility shift assays showed binding of EGR1 to both of these sites upon activation of tumor cells. Furthermore, the heparanase promoter region containing the EGR1 sites was also inducible in tumor cells and induction corresponded to HPSE expression levels. These studies show that EGR1 regulates heparanase transcription in tumor cells and importantly, can have a repressive or activating role depending on the tumor type.

Animals↗
PubMed2005

GM-CSF promoter chromatin remodelling and gene transcription display distinct signal and transcription factor requirements.

Granulocyte-macrophage colony stimulating factor (GM-CSF) plays a key role in myeloid cell function and is rapidly and transiently expressed in T cells in response to immune or inflammatory stimuli. Induction of GM-CSF gene expression is accompanied by changes in chromatin structure across the proximal promoter region of the gene. We show that the promoter remodelling and subsequent gene transcription occurs with distinct signal and transcription factor requirements. Activation of the protein kinase C (PKC) signalling pathway is sufficient to induce changes in chromatin structure across the promoter, but both the PKC and calcium signalling pathways are required for efficient gene transcription. Although NFAT transcription factors contribute to GM-CSF gene transcription, they are not required for promoter remodelling. However, the presence of the nuclear factor-kappaB transcription factor, c-Rel, in the nucleus is strongly correlated with and required for the events of chromatin remodelling.

Animals↗
PubMed2005

Optimizing microarray in experimental hypertension.

BACKGROUND: Genetic noise between outbred animals can potentially be a major confounder in the use of microarray technology for gene expression profiling. The study of paired organs from the same animal offers an alternative approach (e.g., for studies of the kidney in experimental hypertension). The present study was undertaken to determine the level of genetic noise between outbred adult Sprague-Dawley (SD) rats, and to determine the effects of unilateral nephrectomy on changes in gene expression as a basis for the design of microarray studies in experimental hypertension. METHODS: Male SD rats (approximately 130 g) were acclimatized before measurement of tail-cuff systolic blood pressure (SBP) for 6 control days and 4 days of saline treatment. Left kidney nephrectomy was performed, and the tissue snap-frozen in liquid nitrogen for subsequent RNA extraction. Two weeks later, SBP was measured over 4 control and 8 saline treatment days, and the remaining right kidney removed and frozen. Total RNA purification, preparation of cRNA, hybridization, and scanning of the Rat U34A Affymetrix arrays were performed, and data analyzed using MAS5 software Affymetrix Suite (v5), Bioconductor, as well as statistical methods motivated by relevant simulations. RESULTS: Gene expression profiles in the left control kidney were extremely consistent across animals. The expression profiles of pairs of kidneys from the same animal were, however, more similar than those of kidneys from different animals. Nephrectomy had little effect on the gene expression profiles in the time frame examined. CONCLUSION: Despite the outbred nature of the rats used in this study, they are useful for gene expression profiling comparisons. The use of paired organs from an individual animal ensures even further genetic identity, allowing determination of genes modified by the treatment of interest.

Animals↗
PubMed2004

Acephalus acardiac fetus.

Acephalus Acardia is an uncommon congenital malformation due to twin reverse arterial perfusion syndrome. In this condition the donor twin provides circulation for itself and the recipient acardiac twin. The acardiac twin is grossly abnormal with severe reduction anomalies of the upper part of the body. We report a case with autopsy findings and review of literature.

Abnormalities, Multiple↗
PubMed2003

Mapping the kinase domain of Janus Kinase 3.

The utilization and impact of parallel synthesis on lead exploration around initial hit oxindole (1) are described. The emergent SAR, analogue design and functional impact will also be detailed.

Adjuvants, Immunologic↗
PubMed2003

c-Rel is required for chromatin remodeling across the IL-2 gene promoter.

IL-2 gene transcription occurs in an activation-dependent manner in T cells responding to TCR and CD28 activation. One of the critical events leading to increased IL-2 transcription is an alteration in chromatin structure across the 300-bp promoter region of the gene. We initially showed that IL-2 gene transcription in CD4(+) primary T cells is dependent on the NF-kappaB family member, c-Rel, but not RelA. We found that c-Rel is essential for global changes in chromatin structure across the 300-bp IL-2 promoter in response to CD3/CD28 in primary CD4(+) T cells, but not in response to pharmacological signals, paralleling the requirement for c-Rel in IL-2 mRNA and protein accumulation. Interestingly, measurement of activation-induced localized accessibility changes using restriction enzyme digestion revealed that accessibility close to the c-Rel binding site in the CD28RR region of the promoter is specifically dependent on c-Rel. In contrast, restriction enzyme sites located at a distance from the CD28RR behave independently of c-Rel. These results suggest a nonredundant role for c-Rel in generating a correctly remodeled chromatin state across the IL-2 promoter and imply that the strength of the signal determines the requirement for c-Rel.

Animals↗
PubMed2003

Changes in chromatin accessibility across the GM-CSF promoter upon T cell activation are dependent on nuclear factor kappaB proteins.

Granulocyte/macrophage colony-stimulating factor (GM-CSF) is a key cytokine in myelopoiesis and aberrant expression is associated with chronic inflammatory disease and myeloid leukemias. This aberrant expression is often associated with constitutive nuclear factor (NF)-kappaB activation. To investigate the relationship between NF-kappaB and GM-CSF transcription in a chromatin context, we analyzed the chromatin structure of the GM-CSF gene in T cells and the role of NF-kappaB proteins in chromatin remodeling. We show here that chromatin remodeling occurs across a region of the GM-CSF gene between -174 and +24 upon T cell activation, suggesting that remodeling is limited to a single nucleosome encompassing the proximal promoter. Nuclear NF-kappaB levels appear to play a critical role in this process. In addition, using an immobilized template assay we found that the ATPase component of the SWI/SNF chromatin remodeling complex, brg1, is recruited to the GM-CSF proximal promoter in an NF-kappaB-dependent manner in vitro. These results suggest that chromatin remodeling across the GM-CSF promoter in T cells is a result of recruitment of SWI/SNF type remodeling complexes by NF-kappaB proteins binding to the CD28 response region of the promoter.

CD28 Antigens↗
PubMed2003

McCune Albright Syndrome (MCAS): a case series.

McCune Albright Syndrome (MCAS) is an association of, Café-au-lait macules, polyostotic fibrous dysplasia and autonomous hyperfunctioning endocrinopathy. This is a rare disorder seen more commonly in females. We evaluated 7 (6F & 1M) cases under six years of age (4 months to 5.5 yrs) presenting with Café-au-lait spots, polyostotic fibrous dysplasia and/or sexual precocity. All the 7 cases had large Café-au-lait spots, radiologic features of polyostotic fibrous dysplasia were seen in 5 cases. Six girls had precocious puberty with large ovarian follicles and elevated S. Estradiol levels (14-65 pg/dl) with prepubertal gonadotropin levels in 5 of them. Medroxy-progrestrone acetate was used to treat the sexual precocity. Five girls on follow up for 6 months (6mo-16mo) showed cessation of menstrual episodes and regression of ovarian follicles in three, regression in breast size in one, and three girls continued to grow at a height velocity >95th centile for age. Skeletal lesions and skin features did not show any change. No other endocrinopathy was noted. Gonadotropin independent precocious puberty was the only endocrine affection seen in this series.

Cafe-au-Lait Spots↗
PubMed2002

Coordinated interaction of neurogenesis and angiogenesis in the adult songbird brain.

Neurogenesis proceeds throughout life in the higher vocal center (HVC) of the adult songbird neostriatum. Testosterone induces neuronal addition and endothelial division in HVC. We asked if testosterone-induced angiogenesis might contribute importantly to HVC neuronal recruitment. Testosterone upregulated both VEGF and its endothelial receptor, VEGF-R2/Quek1/KDR, in HVC. This yielded a burst in local HVC angiogenesis. FACS-isolated HVC endothelial cells produced BDNF in a testosterone-dependent manner. In vivo, HVC BDNF rose by the third week after testosterone, lagging by over a week the rise in VEGF and VEGF-R2. In situ hybridization revealed that much of this induced BDNF mRNA was endothelial. In vivo, both angiogenesis and neuronal addition to HVC were substantially diminished by inhibition of VEGF-R2 tyrosine kinase. These findings suggest a causal interaction between testosterone-induced angiogenesis and neurogenesis in the adult forebrain.

Animals↗