Seemi Farhat Basir

Administration of estradiol and progesterone modulate the activities of antioxidant enzyme and aminotransferases in naturally menopausal rats.

In aging tissues the oxidative stress increases due to decreased activity of antioxidant enzymes and proteolysis increases due to decreased activity of aminotransferases, which can be modified by hormonal replacement therapy (HRT). The aim of the present study was to determine the effect of HRT on the activities of an antioxidant enzyme superoxide dismutase (SOD) and aminotransferases like alanine aminotransferase (Ala-AT) and aspartate aminotransferase in different age groups (12, 18 and 24 months) of naturally menopausal rats. The rats were given the subcutaneous injection of 17beta-estradiol, progesterone and combination of estradiol and progesterone for 1 month. The activity of SOD, Ala-AT and Asp-AT was measured in the brain (cerebral hemisphere, CH), heart, liver, kidney and uterus. The activity of SOD decreased with age in all the tissues taken particularly in liver. After HRT the enzyme activities were increased as compared to age-matched controls in all the tissues of aging rats. The activities of transaminases (Ala-AT and Asp-AT) showed a decrease with age in all the tissues and administration of estradiol and combination of estradiol and progesterone further decreased both the aminotransferases. Our study elucidates that increased activity of SOD contributes in protection of cells from oxygen toxicity by catalyzing the dismutation of free radicals in tissues. Furthermore, the HRT probably decreases gluconeogenesis and proteolysis by decreasing the activities of Ala-AT and Asp-AT in aging rat tissues.

Proteomic and Transcriptomic Analysis of Aspergillus fumigatus on Exposure to Amphotericin B

ABSTRACT Amphotericin B (AMB) is the most widely used polyene antifungal drug for the treatment of systemic fungal infections, including invasive aspergillosis. It has been our aim to understand the molecular targets of AMB in Aspergillus fumigatus by genomic and proteomic approaches. In transcriptomic analysis, a total of 295 genes were found to be differentially expressed (165 upregulated and 130 downregulated), including many involving the ergosterol pathway, cell stress proteins, cell wall proteins, transport proteins, and hypothetical proteins. Proteomic profiles of A. fumigatus alone or A. fumigatus treated with AMB showed differential expression levels for 85 proteins (76 upregulated and 9 downregulated). Forty-eight of them were identified with high confidence and belonged to the above-mentioned categories. Differential expression levels for Rho-GDP dissociation inhibitor (Rho-GDI), secretory-pathway GDI, clathrin, Sec 31 (a subunit of the exocyst complex), and RAB GTPase Ypt51 in response to an antifungal drug are reported here for the first time and may represent a specific response of A. fumigatus to AMB. The expression of some of these genes was validated by real-time reverse transcription-PCR. The AMB responsive genes/proteins observed to be differentially expressed in A. fumigatus may be further explored for novel drug development.

Aberrant expression and constitutive activation of STAT3 in cervical carcinogenesis: implications in high-risk human papillomavirus infection

BackgroundRecent observations indicate potential role of transcription factor STAT3 in cervical cancer development but its role specifically with respect to HPV infection is not known. Present study has been designed to investigate expression and activation of STAT3 in cervical precancer and cancer in relation to HPV infection during cervical carcinogenesis. Established cervical cancer cell lines and prospectively-collected cervical precancer and cancer tissues were analyzed for the HPV positivity and evaluated for STAT3 expression and its phosphorylation by immunoblotting and immunohistochemistry whereas STAT3-specific DNA binding activity was examined by gel-shift assays.ResultsAnalysis of 120 tissues from cervical precancer and cancer lesions or from normal cervix revealed differentially high levels of constitutively active STAT3 in cervical precancer and cancer lesions, whereas it was absent in normal controls. Similarly, a high level of constitutively active STAT3 expression was observed in HPV-positive cervical cancer cell lines when compared to that of HPV-negative cells. Expression and activity of STAT3 were found to change as a function of severity of cervical lesions from precancer to cancer. Expression of active pSTAT3 was specifically high in cervical precancer and cancer lesions found positive for HPV16. Interestingly, site-specific accumulation of STAT3 was observed in basal and suprabasal layers of HPV16-positive early precancer lesions which is indicative of possible involvement of STAT3 in establishment of HPV infection. In HPV16-positive cases, STAT3 expression and activity were distinctively higher in poorly-differentiated lesions with advanced histopathological grades.ConclusionWe demonstrate that in the presence of HPV16, STAT3 is aberrantly-expressed and constitutively-activated in cervical cancer which increases as the lesion progresses thus indicating its potential role in progression of HPV16-mediated cervical carcinogenesis.

Identification and characterization of a laminin-binding protein of Aspergillus fumigatus: extracellular thaumatin domain protein (AfCalAp).

Aspergillus fumigatus, an opportunistic fungal pathogen, infects the human host via inhalation of airborne conidia. Adhesion of fungal conidia, to host cells and extracellular matrix (ECM) components associated with host tissue surfaces, is thought to be the primary step in the pathogenesis and dissemination of infection. To identify novel adhesion proteins (adhesins) of A. fumigatus, we screened its proteome in silico using SPAAN (software program for prediction of adhesins and adhesin-like proteins using neural networks). One of the predicted adhesin-encoding genes with a P(ad) (probability of being adhesin) value >0.9, the gene encoding extracellular thaumatin domain protein (AfCalA), was cloned and expressed in Escherichia coli. Recombinant AfCalAp showed significant binding with laminin and murine lung cells. Anti-AfCalAp antibodies inhibited the binding of AfCalAp to laminin in a dose-dependent manner. Significant binding of anti-AfCalAp antibodies to 2 h swollen conidia suggests the presence of AfCalAp on the conidial surface. AfCalA transcript was not detectable in resting conidia but was detected in conidia incubated with RPMI 1640 medium in the presence and absence of lung epithelial cell line (A539)-derived ECM. Elevated levels of IgE antibodies specific to AfCalAp were observed in the sera of two out of seven patients with allergic bronchopulmonary aspergillosis. The study confirms the relevance of the bioinformatic approach for predicting fungal adhesins and establishes AfCalAp as a novel laminin-binding protein of A. fumigatus.

Kras Gene Mutation and RASSF1A, FHIT and MGMT Gene Promoter Hypermethylation: Indicators of Tumor Staging and Metastasis in Adenocarcinomatous Sporadic Colorectal Cancer in Indian Population

Objective Colorectal cancer (CRC) development involves underlying modifications at genetic/epigenetic level. This study evaluated the role of Kras gene mutation and RASSF1A, FHIT and MGMT gene promoter hypermethylation together/independently in sporadic CRC in Indian population and correlation with clinicopathological variables of the disease. Methods One hundred and twenty four consecutive surgically resected tissues (62 tumor and equal number of normal adjacent controls) of primary sporadic CRC were included and patient details including demographic characteristics, lifestyle/food or drinking habits, clinical and histopathological profiles were recorded. Polymerase chain reaction - Restriction fragment length polymorphism and direct sequencing for Kras gene mutation and Methylation Specific-PCR for RASSF1A, FHIT and MGMT genes was performed. Results Kras gene mutation at codon 12 & 13 and methylated RASSF1A, FHIT and MGMT gene was observed in 47%, 19%, 47%, 37% and 47% cases, respectively. Alcohol intake and smoking were significantly associated with presence of Kras mutation (codon 12) and MGMT methylation (p-value <0.049). Tumor stage and metastasis correlated with presence of mutant Kras codon 12 (p-values 0.018, 0.044) and methylated RASSF1A (p-values 0.034, 0.044), FHIT (p-values 0.001, 0.047) and MGMT (p-values 0.018, 0.044) genes. Combinatorial effect of gene mutation/methylation was also observed (p-value <0.025). Overall, tumor stage 3, moderately differentiated tumors, presence of lymphatic invasion and absence of metastasis was more frequently observed in tumors with mutated Kras and/or methylated RASSF1A, FHIT and MGMT genes. Conclusion Synergistic interrelationship between these genes in sporadic CRC may be used as diagnostic/prognostic markers in assessing the overall pathological status of CRC.

Functional Regulatory Role of STAT3 in HPV16-Mediated Cervical Carcinogenesis

Signal transducer and activator of transcription 3 (STAT3) is an oncogenic transcription factor constitutively active and aberrantly expressed in cervical cancer. However, the functional role of STAT3 in regulation of HPVs viral oncogene expression and downstream events associated with cervical carcinogenesis is not known. Our present study performed on HPV16-positive cervical cancer cell lines (SiHa and CaSki) and primary tumor tissues revealed a strong positive correlation of constitutively active STAT3 with expression of HPV16 E6 and E7 oncoproteins and a negative association with levels of p53 and pRB. Pharmacologic targeting of STAT3 expression in cervical cancer cell lines either by STAT3-specific siRNA or blocking its tyrosine phosphorylation by AG490 or curcumin led to dose-dependent accumulation of p53 and pRb in cervical cancer cells. Interestingly, the suppression of STAT3 expression or activation was associated with the gradual loss of HPV16 E6 and E7 expression and was accompanied by loss of cell viability. The viability loss was specifically high in HPV16-positive cells as compared to HPV negative C33a cells. These findings substantiate the regulatory role of STAT3 in HPV16-mediated cervical carcinogenesis. Leads obtained from the present study provide a strong rationale for developing novel STAT3-based approaches for therapeutic interventions against HPV infection to control cervical cancer.

HEPATITIS B VIRUS GENOTYPES AND HEPATITIS B SURFACE ANTIGEN MUTATIONS IN FAMILY CONTACTS OF HEPATITIS B VIRUS INFECTED PATIENTS WITH OCCULT HEPATITIS B VIRUS INFECTION

Background:  The association and profile of surface gene mutations with viral genotypes have been studied in patients with chronic hepatitis B virus (HBV) but not in subjects with occult HBV infection.

Effect of estradiol and progesterone treatment on carbohydrate metabolizing enzymes in tissues of aging female rats

The aim of this study was to determine the effect of administration of estradiol (E2), progesterone (P4), and combination of estradiol and progesterone (EP) in aging female rats. The changes in the activities of hexokinase (HK), glucose-6-phosphatase (G6P′tase) and glucose-6-phosphate dehydrogenase (G6PDH) enzymes, and in protein levels in tissues of rats namely brain (cerebral hemisphere), heart, liver, kidney and uterus have been measured in different age groups. The random blood sugar level was measured in serum and liver. The different age groups of rats were given 0.1 μg/g body weight estradiol, 2.5 μg/g body weight progesterone and a similar concentration of both in a combined treatment for 1 month. This dose was selected after determining estrogen and progesterone levels in 3 month adult female animals so that the aging female animals had circulating hormone levels nearly the same as those of young female animals. The random sugar level was determined in serum and liver cytosolic fractions, and it was increased by combination treatment. The protein content in tissues showed significant changes only with combined hormone administration when compared with age-matched controls. The activity of HK decreased in aged animals and significantly increased by hormone treatments in all the tissues of the aged rats studied. The activity of G6P′tase increased with age up to 1.5 years and decreased in 2 years. Treatment with E2 and EP further decreased the activity significantly in all the tissues. G6PDH showed a similar pattern as was observed in HK in all the age groups. Therefore, the E2 and EP treatments caused an entire series of growth-related responses, including an increased uptake of glucose, increased the protein level in the tissues of aging rats, thereby reducing the risk factors associated with aging by normalizing hormone levels which decreased with aging and resulted in diseases such as Alzheimers diseases and diabetes.

Estradiol and progesterone treatments change the lipid profile in naturally menopausal rats from different age groups.

The effect of estradiol and progesterone therapy in serum and liver on the lipid profile of naturally menopausal albino rats of the Wistar strain of different age groups (12,18 and 24months) have been measured and compared with the age matched groups. Three months old rats were used as young controls. The aged rats were administered subcutaneous injection of 17-β-estradiol (0.1 μg/g body weight), progesterone (2.5 μg/g body weight) and similar concentrations of both in combined treatment for 1month and the level of triglycerides (TG), total lipids (TL), total cholesterol (TC), high density lipoprotein (HDL), low density lipoprotein (LDL) and very low density lipoprotein (VLDL) were measured in serum and liver of 3, 12, 18 and 24months old control as well as treated groups. The results show that TG, HDL, VLDL levels were increased significantly by 71%, 155%, 54%, respectively in liver of 24months old rats by combination treatment when compared with age matched control animals. The levels of TL, TC and LDL were decreased by 20%, 31%, and 30%, respectively in serum of 12 months old rats in combination treatment group. The effect was more significant in 12 and 24 months old female rats with administration of estrogen and combined (EP) treatments. The results indirectly suggest that hormone replacement therapy (HRT) can reduce the risk of cardiovascular disease (CVD) thereby playing a cardio-protective role by restoring lipid and hormone levels to the similar levels as found in young female animals.

Glutamine synthetase encoded by glnA-1 is necessary for cell wall resistance and pathogenicity of Mycobacterium bovis.

Pathogenic strains of mycobacteria produce copious amounts of glutamine synthetase (GS) in the culture medium. The enzyme activity is linked to synthesis of poly-α-l-glutamine (PLG) in the cell walls. This study describes a glnA-1 mutant of Mycobacterium bovis that produces reduced levels of GS. The mutant was able to grow in enriched 7H9 medium without glutamine supplementation. The glnA-1 strain contained no detectable PLG in the cell walls and showed marked sensitivity to different chemical and physical stresses such as lysozyme, SDS and sonication. The sensitivity of the mutant to two antitubercular drugs, rifampicin and d-cycloserine, was also increased. The glnA-1 strain infected THP-1 cells with reduced efficiency and was also attenuated for growth in macrophages. A Mycobacterium smegmatis strain containing the M. bovis glnA-1 gene survived longer in THP-1 cells than the wild-type strain and also produced cell wall-associated PLG. The M. bovis mutant was not able to replicate in the organs of BALB/c mice and was cleared within 4-6 weeks of infection. Disruption of the glnA-1 gene adversely affected biofilm formation on polystyrene surfaces. The results of this study demonstrate that the absence of glnA-1 not only attenuates the pathogen but also affects cell surface properties by altering the cell wall chemistry of the organism via the synthesis of PLG; this may be a target for drug development.