Molecular Transducers of Physical Activity Consortium (MoTrPAC): Mapping the Dynamic Responses to Exercise.

Exercise provides a robust physiological stimulus that evokes cross-talk among multiple tissues that when repeated regularly (i.e., training) improves physiological capacity, benefits numerous organ systems, and decreases the risk for premature mortality. However, a gap remains in identifying the detailed molecular signals induced by exercise that benefits health and prevents disease. The Molecular Transducers of Physical Activity Consortium (MoTrPAC) was established to address this gap and generate a molecular map of exercise. Preclinical and clinical studies will examine the systemic effects of endurance and resistance exercise across a range of ages and fitness levels by molecular probing of multiple tissues before and after acute and chronic exercise. From this multi-omic and bioinformatic analysis, a molecular map of exercise will be established. Altogether, MoTrPAC will provide a public database that is expected to enhance our understanding of the health benefits of exercise and to provide insight into how physical activity mitigates disease

Correlation of Chromosomal Instability, Telomere Length and Telomere Maintenance in Microsatellite Stable Rectal Cancer: A Molecular Subclass of Rectal Cancer

<div><p>Introduction</p><p>Colorectal cancer (CRC) tumor DNA is characterized by chromosomal damage termed chromosomal instability (CIN) and excessively shortened telomeres. Up to 80% of CRC is microsatellite stable (MSS) and is historically considered to be chromosomally unstable (CIN+). However, tumor phenotyping depicts some MSS CRC with little or no genetic changes, thus being chromosomally stable (CIN-). MSS CIN- tumors have not been assessed for telomere attrition. </p> <p>Experimental Design</p><p>MSS rectal cancers from patients ≤50 years old with Stage II (B2 or higher) or Stage III disease were assessed for CIN, telomere length and telomere maintenance mechanism (telomerase activation [TA]; alternative lengthening of telomeres [ALT]). Relative telomere length was measured by qPCR in somatic epithelial and cancer DNA. TA was measured with the TRAPeze assay, and tumors were evaluated for the presence of C-circles indicative of ALT. p53 mutation status was assessed in all available samples. DNA copy number changes were evaluated with Spectral Genomics aCGH. </p> <p>Results</p><p>Tumors were classified as chromosomally stable (CIN-) and chromosomally instable (CIN+) by degree of DNA copy number changes. CIN- tumors (35%; n=6) had fewer copy number changes (<17% of their clones with DNA copy number changes) than CIN+ tumors (65%; n=13) which had high levels of copy number changes in 20% to 49% of clones. Telomere lengths were longer in CIN- compared to CIN+ tumors (p=0.0066) and in those in which telomerase was not activated (p=0.004). Tumors exhibiting activation of telomerase had shorter tumor telomeres (p=0.0040); and tended to be CIN+ (p=0.0949).</p> <p>Conclusions</p><p>MSS rectal cancer appears to represent a heterogeneous group of tumors that may be categorized both on the basis of CIN status and telomere maintenance mechanism. MSS CIN- rectal cancers appear to have longer telomeres than those of MSS CIN+ rectal cancers and to utilize ALT rather than activation of telomerase. </p> </div

Histology, C-circle dot blot and aCGH summary for a MSS CIN- ALT + rectal cancer without activation of telomerase and MSS CIN+ ALT - rectal cancer with activation of telomerase.

<div><p>Panel A. Hematoxylin and Eosin tissue sections from an MSS CIN- , ALT+,Telomerase- rectal cancer (left) and from MSS CIN+, ALT-, Telomerase + rectal cancer. Both are moderately differentiated adenocarcinomas. The gland-to-stroma ratio is higher in the ALT+/tel- case, and it has less desmoplastic stroma.</p> <p>Panel B. Dot/blot showing presence of C-circles. C circles, extrachromosomal telomeric DNA, are strongly associated with ALT. Assessed in tumor DNA with isothermic amplification of C-circle complementary strand and hybridization with ³²P-(CCCTAA)₃ probe by Capital Biosciences (Capital Biosciences, Maryland, U. S. A. ), a sample was called ALT+ if C-circles were detected. The presence of C-circles are illustrated by the presence of radioactive tracer in the image on the left, and the absence of radioactivity in the blot on the right indicates absence of C-circles in the ALT- tumor. </p> <p>Panel C. Ideograms summarizing chromosomal gains and losses across all chromosomes evaluated by aCGH. The ALT+, telomerase negative tumor on the left had <10% of BAC clones showing aberrant hybridization and is classified as a CIN- tumor. The ALT-,,telomerase positive tumor on the right had 40% of clones with aberrant hybridization and is classified as a CIN+ tumor. </p> <p>Panel D. aCGH results of raw data for chromosome 17 for each tumor corresponding to the ideograms in Panel C. </p></div

Clone gains/losses by ALT activity.

<p>Tumors that were ALT- exhibited significantly more chromosomal gains/losses than ALT+ rectal cancer (p=0.0091).</p

Telomere length in tumor DNA based on CIN status and telomerase activation.

<div><p>Panel A: The telomere length of tumor DNA in chromosomally stable (CIN-) rectal cancer is significantly longer than that of chromosomally unstable (CIN+) rectal cancer (p=0.0066). CIN status is determined as CIN- if from <20% of clones show DNA copy number gains or losses. Rectal cancer is CIN+ if more than 20% of clones have gains or losses. </p> <p>Panel B: Activation of telomerase (Telomerase +) in rectal cancer correlates with shorter tumor telomere length than in tumors that do not utilize telomerase (Telomerase -) as a telomere maintenance mechanism (p=0.0040).</p></div

Formation of ovarian follicular fluid may be due to the osmotic potential of large glycosaminoglycans and proteoglycans

Copyright © 2006 by the Society for Reproduction and Fertility.During mammalian follicle development, a fluid-filled antrum develops in the avascular centre of the follicle. We investigated the hypothesis that follicular fluid contains osmotically-active molecules, sufficiently large so as to not freely escape the follicular fluid. Such molecules could generate an osmotic differential and thus recruit fluid from the surrounding vascularised stroma into the antrum. Follicular fluid was collected from bovine follicles classified histologically as healthy (n = 4 pools) or atretic (n = 4 pools). Dialysis of the follicular fluid at 300 kDa or 500 kDa resulted in a reduction in colloid osmotic pressure of 35% and 60%, respectively, in fluid from healthy follicles and 29% and 80% from atretic follicles. Digestion of follicular fluid with Streptomyces hyaluronidase, chondroitinase ABC or DNase 1 followed by dialysis resulted in reductions in osmotic pressure of 43%, 53% and 43% respectively for fluids from healthy follicles and 34%, 20% and 31% for atretic follicles. Digestion with collagenase I, proteinase K, heparanase 1 or keratanase had no significant effect on the osmotic pressure of follicular fluid of healthy follicles. Ion exchange and size exclusion, Western blotting and ELISA identified the proteoglycans versican and inter-alpha trypsin inhibitor and the glycosaminoglycan hyaluronan in follicular fluid. We conclude that these molecules or aggregates of them are of sufficient size to contribute to the osmotic potential of follicular fluid and thus recruit fluid into the follicular antrum. DNA may also contribute but it is probably not a component that is regulated for this role.Hannah G Clarke, Sarah A Hope, Sharon Byers, and Raymond J Rodger