Intensive resistance exercise induces lymphocyte apoptosis via cortisol and glucocorticoid receptor-dependent pathways

Intensive endurance exercise is known to induce lymphocyte apoptosis, which might affect immune function. Less is known about the effects of resistance exercise on apoptosis and its underlying mechanisms. In this study, subjects performed an intensive resistance test (IRT) and a moderate resistance test, and lymphocyte apoptosis, apoptosis-related parameters, and underlying mechanisms were investigated. IRT induced a significant increase of lymphocyte apoptosis 3 h after exercise, which was accompanied by a significant decrease of mitochondrial membrane potential, a reduction of Bcl-2, and an upregulation of the CD95 receptor. Blood lactate, IL-6, C-reactive protein, and cortisol increased significantly 3 h after IRT. A significant correlation was observed between the increase of apoptosis and cortisol levels 3 h after IRT. Incubation of freshly isolated lymphocytes in IRT serum indicated an important role of serum correlates for apoptosis induction. Selective incubation of lymphocytes in concentrations of selected serum parameters corresponding to levels found post in IRT serum demonstrated a major role for cortisol in apoptosis induction. This result was confirmed by attenutation of apoptosis after addition of mifepristone before incubation in IRT serum. In summary, resistance exercise induced lymphocyte apoptosis in an intensity-dependent way. Furthermore, cortisol signaling via glucocorticoid receptors might be an important mechanism for lymphocyte apoptosis after resistance exercise.     

Production and characterization of somatic hybrids between <Emphasis Type="Italic">Solanum tuberosum</Emphasis> L. and <Emphasis Type="Italic">S. pinnatisectum</Emphasis> Dun.

Interspecific somatic hybrids between the dihaploid Solanum tuberosum and the wild species S. pinnatisectum Dun. were produced via protoplast fusion. Protoplast isolation, electrofusion, culture of post-fusion products and regeneration of calli/shoots were undertaken following optimized protocols. Regenerants were characterized for hybridity, ploidy and resistance to Phytophthora infestans (Mont.) de Bery, causal fungal pathogen of late blight disease. From a total of 126 regenerated macrocalli, 12 somatic hybrids were confirmed by possessing species-specific diagnostic bands of their corresponding parents as revealed by RAPD, SSRs and cytoplasmic-DNA analyses. Tetraploid status of the 12 hybrids was determined using flow cytometry analysis. Intermediate phenotypes for leaf, flower, and tuber characteristics and high male fertility were observed in field-grown hybrid plants. Hybrids were highly resistant to foliage late blight based on field assessment for two seasons. In contrast, moderate level of resistance to foliage blight was observed in hybrids based on the detached leaf assay under laboratory conditions. Overall, somatic hybrids with moderate levels of resistance to foliage blight were identified, and these will be useful for in situ hybridization in potato breeding efforts.     

Click chemistry inspired one-pot synthesis of 1,4-disubstituted 1,2,3-triazoles and their Src kinase inhibitory activity

Two classes of 1,4-disubstituted 1,2,3-triazoles were synthesized using one-pot reaction of α-tosyloxy ketones/α-halo ketones, sodium azide, and terminal alkynes in the presence of aq PEG (1:1, v/v) using the click chemistry approach and evaluated for Src kinase inhibitory activity. Structure-activity relationship analysis demonstrated that insertion of C₆H₅- and 4-CH₃C₆H₄- at position 4 for both classes and less bulkier aromatic group at position 1 in class 1 contribute critically to the modest Src inhibition activity (IC₅₀ = 32-43 μM) of 1,4-disubstituted 1,2,3-triazoles.     

Synthesis of 3-phenylpyrazolopyrimidine-1,2,3-triazole conjugates and evaluation of their Src kinase inhibitory and anticancer activities

A series of two classes of 3-phenylpyrazolopyrimidine-1,2,3-triazole conjugates were synthesized using click chemistry approach. All compounds were evaluated for inhibition of Src kinase and human ovarian adenocarcinoma (SK-Ov-3), breast carcinoma (MDA-MB-361), and colon adenocarcinoma (HT-29). Hexyl triazolyl-substituted 3-phenylpyrazolopyrimidine exhibited inhibition of Src kinase with an IC₅₀ value of 5.6 μM. 4-Methoxyphenyl triazolyl-substituted 3-phenylpyrazolopyrimidine inhibited the cell proliferation of HT-29 and SK-Ov-3 by 73% and 58%, respectively, at a concentration of 50 μM.     

Molecular modeling of the human serotonin(1A) receptor: role of membrane cholesterol in ligand binding of the receptor

Serotonin(1A) receptors are important neurotransmitter receptors and belong to the superfamily of G-protein coupled receptors (GPCRs). Although it is an important drug target, the crystal structure of the serotonin(1A) receptor has not been solved yet. Earlier homology models of the serotonin(1A) receptor were generated using rhodopsin as a template. We have used two recent crystal structures of the human β(2)-adrenergic receptor, one of which shows specific cholesterol binding site(s), as templates to model the human serotonin(1A) receptor. Since the sequence similarity between the serotonin(1A) receptor and β(2)-adrenergic receptor is considerably higher than the similarity between the serotonin(1A) receptor and rhodopsin, our model is more reliable. Based on these templates, we generated models of the serotonin(1A) receptor in the absence and presence of cholesterol. The receptor model appears more compact in the presence of cholesterol. We validated the stability of 'compactness' using coarse-grain MD simulation. Importantly, all ligands exhibit higher binding energies when docked to the receptor in the presence of cholesterol, thereby implying that membrane cholesterol facilitates ligand binding to the serotonin(1A) receptor. To the best of our knowledge, this is one of the first reports in which lipid-specific receptor conformations have been modeled by homology modeling.     

Estrogen induced metastatic modulators MMP-2 and MMP-9 are targets of 3,3'-diindolylmethane in thyroid cancer

Background

Thyroid cancer is the most common endocrine related cancer with increasing incidences during the past five years. Current treatments for thyroid cancer, such as surgery or radioactive iodine therapy, often require patients to be on lifelong thyroid hormone replacement therapy and given the significant recurrence rates of thyroid cancer, new preventive modalities are needed. The present study investigates the property of a natural dietary compound found in cruciferous vegetables, 3,3′-diindolylmethane (DIM), to target the metastatic phenotype of thyroid cancer cells through a functional estrogen receptor.

Methodology/Principal Findings

Thyroid cancer cell lines were treated with estrogen and/or DIM and subjected to in vitro adhesion, migration and invasion assays to investigate the anti-metastatic and anti-estrogenic effects of DIM. We observed that DIM inhibits estrogen mediated increase in thyroid cell migration, adhesion and invasion, which is also supported by ER-α downregulation (siRNA) studies. Western blot and zymography analyses provided direct evidence for this DIM mediated inhibition of E₂ enhanced metastasis associated events by virtue of targeting essential proteolytic enzymes, namely MMP-2 and MMP-9.

Conclusion/Significance

Our data reports for the first time that DIM displays anti-estrogenic like activity by inhibiting estradiol enhanced thyroid cancer cell proliferation and in vitro metastasis associated events, namely adhesion, migration and invasion. Most significantly, MMP-2 and MMP-9, which are known to promote and enhance metastasis, were determined to be targets of DIM. This anti-estrogen like property of DIM may lead to the development of a novel preventive and/or therapeutic dietary supplement for thyroid cancer patients by targeting progression of the disease.     

Genome-wide detection of allele specific copy number variation associated with insulin resistance in African Americans from the HyperGEN study

African Americans have been understudied in genome wide association studies of diabetes and related traits. In the current study, we examined the joint association of single nucleotide polymorphisms (SNPs) and copy number variants (CNVs) with fasting insulin and an index of insulin resistance (HOMA-IR) in the HyperGEN study, a family based study with proband ascertainment for hypertension. This analysis is restricted to 1,040 African Americans without diabetes. We generated allele specific CNV genotypes at 872,243 autosomal loci using Birdsuite, a freely available multi-stage program. Joint tests of association for SNPs and CNVs were performed using linear mixed models adjusting for covariates and familial relationships. Our results highlight SNPs associated with fasting insulin and HOMA-IR (rs6576507 and rs8026527, 3.7*10(-7)≤P≤1.1*10(-5)) near ATPase, class V, type 10A (ATP10A), and the L Type voltage dependent calcium channel (CACNA1D, rs1401492, P≤5.2*10(-6)). ATP10A belongs to a family of aminophospholipid-transporting ATPases and has been associated with type 2 diabetes in mice. CACNA1D has been linked to pancreatic beta cell generation in mice. The two most significant copy variable markers (rs10277702 and rs361367; P<2.0*10(-4)) were in the beta variable region of the T-cell receptor gene (TCRVB). Human and mouse TCR has been shown to mimic insulin and its receptor and could contribute to insulin resistance. Our findings differ from genome wide association studies of fasting insulin and other diabetes related traits in European populations, highlighting the continued need to investigate unique genetic influences for understudied populations such as African Americans.