Pradeep G. Kumar

Profiling of E-cadherin, β-catenin and Ca2+ in embryo–uterine interactions at implantation

Establishment of early pregnancy is promoted by a complex network of signalling molecules that mediate cell‐to‐cell and cell‐to‐extracellular matrix communications between the receptive endometrium and the invasive trophectoderm. In this study, we have attempted to evaluate the expression profiles of cadherin and catenin during embryo implantation in the mouse. Western blotting studies along with immunocytochemical analysis revealed that E‐cadherin is expressed rather ubiquitously in the uterine epithelial cells, distinct enrichment is observed on the apical membrane in the endometrium of peri‐implantation uterus specifically at the implantation sites and not at the inter‐implanation sites. β‐Catenin also is upregulated and is specifically restricted to apical membrane of epithelial cells of implantation sites. Progesterone induced expression of E‐cadherin and 17β‐estradiol regulated the expression of catenin in implantation‐delayed uteri. Interestingly, estradiol imparted negative modulation on cadherin expression when co‐administered with progesterone. On the contrary, trophoblast exhibits a striking down regulation of cadherin, catenin and Ca2+ at peri implanting stage. These observations suggest that the trophoblasts exhibited an invasive phenotype while the endometrial epithelium displayed an adhesive phenotype during the window of implantation. Thus, embryo implantation presents an instance where two interacting surfaces showed mutually complementing interaction phenotypes.

Thalidomide attenuates nitric oxide-driven angiogenesis by interacting with soluble guanylyl cyclase

Background and purpose:  Nitric oxide (NO) promotes angiogenesis by activating endothelial cells. Thalidomide arrests angiogenesis by interacting with the NO pathway, but its putative targets are not known. Here, we have attempted to identify these targets.

Identification of a Soluble NADPH Oxidoreductase (BmNOX) with Antiviral Activites in the Gut Juice of Bombyx mori

Silkworms show high variability in silk quality and disease resistance. Attempts are on to combine the disease tolerance of multivoltine races and the silk quality of bivoltine races to generate new races with desirable phenotypic traits. We report the identification of a 26.5-kDa protein that is overexpressed in the gut juice of disease-resistant multivoltine races and that has anti-BmNPV activity. We have characterized this protein as a soluble NADH-oxidoreductase-like protein (BmNOX). Treatment of live BmNPV particles with BmNOX inhibited the capability of the viral particles to infect BmN cells in vitro.

Mifepristone (Ru486) antagonizes monocyte chemotactic protein-3 down-regulation at early mouse pregnancy revealing immunomodulatory events in Ru486 induced abortion.

Problem:  The survival of an embryo bearing the paternal antigens within the immunocompetent environment of the maternal uterus renders ‘pregnancy’ to be a state of immunological paradox. The ratio of Th1/Th2 responses is crucial for pregnancy maintenance. Monocyte Chemotactic Protein‐3 (MCP3) is a pro‐inflammatory, CC chemokine and a Th1 effector which is capable of eliciting significant anti‐tumoral immune responses.

Dramatic Changes in 67 miRNAs During Initiation of First Wave of Spermatogenesis in Mus musculus Testis: Global Regulatory Insights Generated by miRNA-mRNA Network Analysis

ABSTRACT We mapped global changes in miRNA and mRNA profiles spanning the first wave of spermatogenesis using prepubertal (Postnatal Day 8 [P8]), pubertal (P16), and adolescent (P24) Mus musculus testes and identified the differential expression of 67 miRNAs and 8226 mRNAs. These two data sets were integrated into miRNA-dependent regulatory networks based on miRWalk predictions. In a network representing the P8 to P16 transition, downregulation of four miRNAs and upregulation of 19 miRNAs were linked with 81 upregulated target mRNAs and 228 downregulated target mRNAs, respectively. Furthermore, during the P16 to P24 transition, two miRNAs were downregulated, and eight miRNAs were upregulated, which linked with 64 upregulated mRNAs and 389 downregulated mRNAs, respectively. Only three of the miRNAs present in the network (miR-34b-5p, miR-34c, and miR-449a) showed a progressive increase from P8 through P16 to P24, while the remaining miRNAs in the network showed statistically significant changes in their levels either during the P8 to P16 transition or during the P16 to P24 transition. Analysis of the chromosomal location of these differentially expressed miRNAs showed that 14 out of 25 miRNAs upregulated from P8 to P16, and 18 out of 40 miRNAs upregulated from P8 to P24 were X-linked. This is suggestive of their escape from meiotic sex chromosome inactivation and postmeiotic sex chromatin. This integrated network of miRNA-level and mRNA-level changes in mouse testis during the first wave of spermatogenesis is expected to build a base for evaluating the role of miRNA-mediated gene expression regulation in maturing mammalian testis.

SUPEROXIDE ANION RADICAL PRODUCTION AS A CADMIUM-MEDIATED MECHANISM OF TOXICITY IN AVIAN THYROID : AN ELECTRON SPIN RESONANCE STUDY BY SPIN TRAPPING

Abstract Cadmium (Cd) induced superoxide anion radical (O ·− 2 ) generation in vivo has been demonstrated in the thyroid gland of Columba livia intermedia by electron spin resonance (ESR) spin trapping. A single dose of Cd caused generation of O ·− 2 , elevated lipid peroxidation (LPO) and superoxide dismutase (SOD) activity and depletion of glutathione (GSH) content in the thyroid gland on the 1st and 3rd day after the treatment. After the 7th and 10th day of Cd intoxication, the thyroid gland resumes normal reducing atmosphere characterized by a very low LPO level, total decay of O ·− 2 and an adaptive recovery of depleted GSH to that of control. A high level of SOD activity over the experimental period and return of GSH content to that of control by the 7th day of treatment till the 10th day suggest their role as a very effective oxyradical scavenging sink during Cd-mediated oxidative assault. A low plasma triiodothyronine (T 3 ) level, decreased plasma T 3 /T 4 ratio over most of the study period and a transient drop in plasma thyroxine (T 4 ) level during early phase of acute poisoning indicate that pigeons are in the hypothyroid state. We propose that avian thyroid dysfunction under acute Cd-exposure is due to impaired thyroid hormonogenesis under an oxidative stress and a direct Cd-inhibition of peripheral monodeiodination of T 4 to T 3 .

The Role of TRP Ion Channels in Testicular Function

Transient receptor potential (TRP) proteins are homologues of Drosophila transient receptor potential ion channels first identified in the photo receptors and reported to be involved in calcium entry following calcium store depletion during photo transduction. TRP is a large super family divided in several families including the TRPC (Canonical) family, the TRPV (Vanilloid) family, the TRPM (Melastatin) family, the TRPP (Polycystin) family, the TRPML (Mucolipin) family, the TRPA (Ankyrin) family, and the TRPN (NOMPC) family. TRP proteins are six transmembrane ion channels and act as components of multimeric complexes which allow cation entry either after internal calcium depletion or in response to receptor stimulation. TRP ion channels have been reported to act as molecular sensors of environment. Trp genes are expressed in a wide range of tissues including testis. In addition to this TRP proteins have also been detected in mature sperm from a number of species including humans. TRP may be involved in regulating calcium dependent functions of sperm including motility, capacitation, and acrosome reaction. Here we review the available information about TRP proteins reported in the sperm, as well as in other cells/tissue systems.

Fluorescence resonance energy transfer between polyphenolic compounds and riboflavin indicates a possible accessory photoreceptor function for some polyphenolic compounds

Abstract The photoreceptive extreme tip of the wheat coleoptile exhibits intense green-yellow fluorescence under UV light, suggesting the presence of UV-absorbing materials. Fluorescence spectra of the intact coleoptile tip and tip homogenate showed the presence of the known photoreceptor pigments flavin and carotene, and a preponderance of phenolic compounds. Absorption spectra and fluorescence spectra of various phenolic compounds showed close overlap with the absorption and fluorescence spectra of the wheat coleoptile tip homogenate. Fluorescence spectra of several phenolic compounds showed close overlap with the absorption bands of flavin, carotene and pterine, suggesting possible energy transduction from phenols to these photoreceptors. Excitation of gentisic acid and ferulic acid with 340 nm light in the presence of flavin showed enhancement of flavin fluorescence in a concentration- and viscosity-dependent fashion, indicating fluorescence resonance energy transfer between them and riboflavin. Furthermore, several phenolic compounds tested generated superoxide anion on excitation at 340 nm, suggesting that superoxide-dependent signal cascades could operate in a polyphenol-mediated pathway. Phenolic compounds thus may act as accessory photoreceptors bringing about excitation energy transfer to the reactive photoreceptor molecules, or they may take over the function of the normal photoreceptor in genetic mutations lacking the system, or both processes may occur. The responses of plants to UV-B and UV-A light in mutants may be explained in terms of various phenolics acting as energy transducers in photoreceptor functioning.

Molecular characterization and expression analysis of BmNOX in two strains of Bombyx mori with contrasting viral resistance phenotype.

We recently documented the identification of a 26.5 kDa protein named BmNox in the gut fluid of Nistari strain of Bombyx mori, which possessed antiviral activity against BmNPV in vitro. In this report, we report the characterization of the full-length gene encoding BmNOX and the levels of expression of this gene in select tissues of silkworm larvae from a BmNPV-susceptible and a BmNPV-resistant strain to the defense capability in Bombyx mori larvae challenged with BmNPV. We also evaluated the BmNox expression in various stages of larval life of a resistant and a susceptible strain of Bombyx mori selected from among a panel of strains of silkworm. Nistari, a multivoltine strain of silkworm, expressed BmNOX during all five larval stages, and were highly resistant to BmNPV infection. In sharp contrast, CSR(2), a bivoltine strain, showed weaker expression of BmNOX in the anterior midgut in larval life and was highly susceptible to BmNPV infection. BmNOX is a secretory protein with dual expression in gut fluid and mid gut tissue. BmNOX is expressed heavily in the posterior mid gut, with weaker expression in the fore- and mid-gut regions.

Aberrant expression of TAR DNA binding protein-43 is associated with spermatogenic disorders in men

Loss of function of TAR DNA-binding protein (TDP-43) has been implicated in neurodegenerative disorders in both humans and animal models. TDP-43 has also been shown to be cis-acting transcriptional repressor of the acrosome vesicle (Acrv) gene in mice. In the present study, we investigated the expression of the TDP-43 transcript (TARDBP) and protein in germ cells from 11 fertile and 98 subfertile men to verify its potential association with poor seminograms. The expression profile of TDP-43 was characterised in immature germ cells and spermatozoa from semen from fertile and subfertile men using reverse transcription-polymerase chain reaction, western blotting and immunofluorescence. Although germ cells from subfertile men tested negative for TARDBP, the full-length message of the same was detected in fertile men. TDP-43 was detected in spermatozoa from fertile men using western blot analysis and immunofluorescence. The expression of this protein was negligible in spermatozoa from men with primary spermatogenic dysfunction. We conclude that a deficiency in the TDP-43 expression is associated with defective spermatogenesis and male infertility. We propose that TDP-43 could be used as a marker of male factor infertility.