Regulation of neurofilament gene expression by thyroid hormone in the developing rat brain

The role of thyroid hormone (TH) in the expression of neurofilament (NF) genes during the first 3-4 postnatal weeks of rat brain development has been examined. I.p. administration of TH to 2-day-old hypothyroid rats resulted in a 2-fold increase in cerebral NF-M and NF-L mRNAs, while administration to 15-day-old hypothyroid rats led to a 1.5- to 3-fold increase in NF-H mRNA within 2-4 h of hormone injection. Comparison of the level of these mRNAs in cerebra from 5, 10, 15 and 20-day-old normal and hypothyroid rats by Northern blot analysis revealed that hypothyroidism declined the expression of all three mRNAs by 50-70% at all ages examined. Western blot analysis of total protein and cytoskeletal proteins isolated from cerebras of 5, 10, 15, 20 and 25-day-old normal and hypothyroid rats demonstrated an even greater reduction (60-90%) in the expression of NF proteins in the hypothyroid cerebra during the period examined. The overall results show that TH plays an important role in regulating the expression of all three NF genes during rat brain development

Dual DNA binding mode of a turn-on red fluorescent probe thiazole coumarin.

Turn-on fluorescent probes show enhanced emission upon DNA binding, advocating their importance in imaging cellular DNA. We have probed the DNA binding mode of thiazole-coumarin (TC) conjugate, a recently reported hemicyanine-based turn-on red fluorescent probe, using a number of biophysical techniques and a series of short oligonucleotides. TC exhibited increased fluorescence anisotropy and decreased absorbance (~50%) at low [DNA]/[TC] ratio. Although the observed hypochromicity and the saturating value of [DNA base pair]:[TC] ratio is consistent with a previous study that suggested intercalation to be the DNA binding mode of TC, a distinctly different and previously unreported binding mode was observed at higher ratios of [DNA]:[TC]. With further addition of DNA, only oligonucleotides containing AnTn or (AT)n stretches showed further change-decreased hypochromicity, red shifted absorption peaks and concomitant fluorescence enhancement, saturating at about 1:1 [DNA]: [TC]. 1H-NMR chemical shift perturbation patterns and H1'-H6/H8 NOE cross-peaks of the 1:1 complex indicated minor groove binding by TC. ITC showed the 1:1 DNA binding event to be endothermic (ΔH° ~ 2 kcal/mol) and entropy driven (ΔS° ~ 32 cal/mol/K). Taken together, the experimental data suggest a dual DNA binding mode by TC. At low [DNA]/[TC] ratio, the dominant mode is intercalation. This switches to minor groove binding at higher [DNA]/[TC], only for sequences containing AnTn or (AT)n stretches. Turn-on fluorescence results only in the previously unreported minor groove bound state. Our results allow a better understanding of DNA-ligand interaction for the newly reported turn-on probe TC

Reduced expression and altered distribution of neurofilaments in neurons cultured in thyroid hormone-deficient medium

The effect of thyroid hormone (TH) defiency on the expression of neurofilament (NF) proteins and their intracellular distribution has been examined in primary cultures of neurons from embryonic rat cerebra. Northern blot analysis showed that in TH-deficient (THdef) neurons, the expression of all three NF mRNAs (NF-L, NF-M and NF-H) are retarded by 50-70% at days 7, 15 and 25 of culture compared with their TH-supplemented (THsup) counterparts. Western blot analysis also showed a decline of 60-80% in the expression of all the NF-proteins at all time points. Immunofluorescent staining of neurons from THdef and THsup cultures at days 7, 15, and 25 with monoclonal anti NF-L antibody showed that with age, TH deficiency reduced the localization of NF-L in the cell body with a corresponding increase in the hillock and proximal axon region. The present neuronal culture system offers an excellent experimental model for studying the biochemical events responsible for the altered NF pathology in degenerating neurons

Hypothyroidism in the Developing Rat Brain is Associated with Marked Oxidative Stress and Aberrant Intraneuronal Accumulation of Neurofilaments

The effects of hypothyroidism on parameters of oxidative stress and on intraneuronal distribution of neurofilaments have been investigated in the developing rat brain. Progressive hypothyroidism during the first 4 weeks of postnatal development led to an increase in superoxide dismutase and catalase activity, decline in the level of glutathione and mitochondrial cytochrome c oxidase activity and increase in the level of �OH radical along with enhanced protein carbonylation and lipid peroxidation. Immunocytochemical staining of cryostat sections of normal and hypothyroid cerebella from 25 day postnatal rats with anti neurofilament (NF) light chain (L) antibody showed aberrant accumulation of neurofilaments in the perikaryon of the hypothyroid Purkinje neurons in contrast to relatively uniform distribution in the controls. The morphological and biochemical alterations in the neurons of the developing hypothyroid brain are comparable to those seen in several neurodegenerative diseases. © 2001 Elsevier Science Ireland Ltd and the Japan Neuroscience Society

Polymorphisms in ADH1B and ALDH2 genes associated with the increased risk of gastric cancer in West Bengal, India

Abstract Background Gastric cancer (GC) is one of the most frequently diagnosed digestive tract cancers and carries a high risk of mortality. Acetaldehyde (AA), a carcinogenic intermediate of ethanol metabolism contributes to the risk of GC. The accumulation of AA largely depends on the activity of the major metabolic enzymes, alcohol dehydrogenase and aldehyde dehydrogenase encoded by the ADH (ADH1 gene cluster: ADH1A, ADH1B and ADH1C) and ALDH2 genes, respectively. This study aimed to evaluate the association between genetic variants in these genes and GC risk in West Bengal, India. Methods We enrolled 105 GC patients (cases), and their corresponding sex, age and ethnicity was matched to 108 normal individuals (controls). Genotyping for ADH1A (rs1230025), ADH1B (rs3811802, rs1229982, rs1229984, rs6413413, rs4147536, rs2066702 and rs17033), ADH1C (rs698) and ALDH2 (rs886205, rs968529, rs16941667 and rs671) was performed using DNA sequencing and RFLP. Results Genotype and allele frequency analysis of these SNPs revealed that G allele of rs17033 is a risk allele (A vs G: OR = 3.67, 95% CI = 1.54–8.75, p = 0.002) for GC. Significant association was also observed between rs671 and incidence of GC (p = 0.003). Moreover, smokers having the Lys allele of rs671 had a 7-fold increased risk of acquiring the disease (OR = 7.58, 95% CI = 1.34–42.78, p = 0.009). Conclusion In conclusion, rs17033 of ADH1B and rs671 of ALDH2 SNPs were associated with GC risk and smoking habit may further modify the effect of rs671. Conversely, rs4147536 of ADH1B might have a protective role in our study population. Additional studies with a larger patient population are needed to confirm our results

Effect of increase in the number of “effective” risk alleles on the risk of Kidney stone disease in combined samples.

<p>OR are plotted on the <i>y</i>-axis for the corresponding number of “effective” risk alleles on the <i>x</i>-axis. Numbers in parentheses on <i>x</i>-axis indicate sample size in each category. <2 group considers as reference group. <2: Individuals having 2 or less “effective” risk alleles. 2- -3: Individuals having 2–3 “effective” risk alleles. 3- -4: Individuals having 3–4 “effective” risk alleles. >4: Individuals having 4 or more “effective” risk alleles.</p