Nest Carbon Dioxide Masks GABA-Dependent Seizure Susceptibility in the Naked Mole-Rat.

African naked mole-rats were likely the first mammals to evolve eusociality, and thus required adaptations to conserve energy and tolerate the low oxygen (O2) and high carbon dioxide (CO2) of a densely populated fossorial nest. As hypercapnia is known to suppress neuronal activity, we studied whether naked mole-rats might demonstrate energy savings in GABAergic inhibition. Using whole-colony behavioral monitoring of captive naked mole-rats, we found a durable nest, characterized by high CO2 levels, where all colony members spent the majority of their time. Analysis of the naked mole-rat genome revealed, uniquely among mammals, a histidine point variation in the neuronal potassium-chloride cotransporter 2 (KCC2). A histidine missense substitution mutation at this locus in the human ortholog of KCC2, found previously in patients with febrile seizures and epilepsy, has been demonstrated to diminish neuronal Cl- extrusion capacity, and thus impairs GABAergic inhibition. Seizures were observed, without pharmacological intervention, in adult naked mole-rats exposed to a simulated hyperthermic surface environment, causing systemic hypocapnic alkalosis. Consistent with the diminished function of KCC2, adult naked mole-rats demonstrate a reduced efficacy of inhibition that manifests as triggering of seizures at room temperature by the GABAA receptor (GABAAR) positive allosteric modulator diazepam. These seizures are blocked in the presence of nest-like levels of CO2 and likely to be mediated through GABAAR activity, based on in vitro recordings. Thus, altered GABAergic inhibition adds to a growing list of adaptations in the naked mole-rat and provides a plausible proximate mechanism for nesting behavior, where a return to the colony nest restores GABA-mediated inhibition.

SOD1 is essential for oncogene-driven mammary tumor formation but dispensable for normal development and proliferation.

We previously reported that the dismutase SOD1 is overexpressed in breast cancer. However, whether SOD1 plays an active role in tumor formation in vivo has never been demonstrated. Further, as luminal cells of normal breast epithelial cells are enriched in SOD1, whether SOD1 is essential for normal mammary gland development has never been determined. We initiated this study to investigate the role of SOD1 in mammary gland tumorigenesis as well as in normal mammary gland development. We crossed the inducible erbB2 (MMTV-iErbB2) and Wnt (MMTV-Wnt) transgenic mice to the SOD1 heterozygote or knockout mice. Our results show that SOD1 is essential for oncogene-driven proliferation, but not normal proliferation of the mammary gland associated with pregnancy or other normal proliferative tissues such as skin and intestines. We show that activation of the oncogene ErbB2 is associated with increased ROS and that high ROS sub-population of ErbB2 cancer cells show elevated SOD1. In the same cells, decrease in SOD1 is associated with an elevation in both apoptosis as well as oncogene-induced senescence. Based on these results, we suggest that SOD1 carries a housekeeping function that maintains ROS levels below a threshold that supports oncogene-dependent proliferation, while allowing escape from oncogene-induced senescence, independently of the oncogene driving tumor formation. These results identify SOD1 as an ideal target for cancer therapy as SOD1 inhibitors hold the potential to prevent the growth of cancers cells of diverse genotypes, activate multiple modes of cell death therefore making acquired resistance more difficult, while sparing normal tissues.

Folate receptor autoantibodies are prevalent in children diagnosed with autism spectrum disorder, their normal siblings and parents.

Folate deficiency can affect fetal and neonatal brain development Considering the reported association of Folate receptor alpha (FRα) autoantibodies (Abs) with autism and developmental disorders, we sought to confirm this in families of 82 children with ASD, 53 unaffected siblings, 65 fathers, and 70 mothers, along with 52 unrelated normal controls. Overall, 76% of the affected children, 75% of the unaffected siblings, 69% of fathers and 59% of mothers were positive for either blocking or binding Ab, whereas the prevalence of this Ab in the normal controls was 29%. The Ab was highly prevalent in affected families including unaffected siblings. The appearance of these antibodies may have a familial origin but the risk of developing ASD is likely influenced by other mitigating factors since some siblings who had the antibodies were not affected. The antibody response appears heritable with the blocking autoantibody in the parents and affected child increasing the risk of ASD. Autism Res 2018, 11: 707-712. © 2018 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Folate is an essential nutrient during fetal and infant development. Autoantibodies against the folate receptor alpha can block folate transport from the mother to the fetus and to the brain in infants. Children diagnosed with autism and their immediate family members were evaluated for the prevalence of folate receptor autoantibodies. The autoantibody was highly prevalent in affected families with similar distribution in parents, normal siblings and affected children. The presence of these antibodies appears to have a familial origin and may contribute to developmental deficits when combined with other factors.

Longitudinal telomere shortening and early Alzheimer's disease progression in adults with down syndrome.

Telomere shortening was shown to parallel Alzheimer's disease (AD) associated dementia. By using a dual PNA Probe system we have developed a practical method for comparing telomere length in T-lymphocyte interphases from individuals with Down syndrome (DS) with and without "mild cognitive impairment" (MCI-DS) and demonstrated that telomere length can serve as a valid biomarker for the onset of MCI-DS in this high-risk population. To verify progressive cognitive decline we have now examined sequential changes in telomere length in 10 adults with DS (N = 4 Female, N = 6 Male) developing MCI-DS. Cases were selected blind to telomere length from a sample of adults with DS previously enrolled in a prospective longitudinal study at 18-month intervals with clinical and telomere assessments: (1) MCI-DS group data were collected approximately three years prior to development of MCI-DS; (2) 18 months later; (3) when MCI-DS was first observed. These telomere measures were compared to those from another 10 adults with DS matched by sex and approximate age but without indications of MCI-DS (Controls). PNA (peptide nucleic acid) probes for telomeres together with a chromosome two centromere probe were used. Findings indicated telomere shortening over time for both Cases and Controls. Group differences emerged by 18-months prior to recognition of MCI-DS onset and completely non-overlapping distributions of telomere measures were observed by the time of MCI-DS onset. This study adds to accumulating evidence of the value of telomere length, as an early biomarker of AD progression in adults with Down syndrome.

Is Taurine a Biomarker in Autistic Spectrum Disorder?

Taurine is a sulfur-containing amino acid which is not incorporated into protein. However, taurine has various critical physiological functions including development of the eye and brain, reproduction, osmoregulation, and immune functions including anti-inflammatory as well as anti-oxidant activity. The causes of autistic spectrum disorder (ASD) are not clear but a high heritability implicates an important role for genetic factors. Reports also implicate oxidative stress and inflammation in the etiology of ASD. Thus, taurine, a well-known antioxidant and regulator of inflammation, was investigated here using the sera from both girls and boys with ASD as well as their siblings and parents. Previous reports regarding taurine serum concentrations in ASD from various laboratories have been controversial. To address the potential role of taurine in ASD, we collected sera from 66 children with ASD (males: 45; females: 21, age 1.5-11.5 years, average age 5.2 ± 1.6) as well as their unaffected siblings (brothers: 24; sisters: 32, age 1.5-17 years, average age 7.0 ± 2.0) as controls of the children with ASD along with parents (fathers: 49; mothers: 54, age 28-45 years). The sera from normal adult controls (males: 47; females: 51, age 28-48 years) were used as controls for the parents. Taurine concentrations in all sera samples were measured using high performance liquid chromatography (HPLC) using a phenylisothiocyanate labeling technique. Taurine concentrations from female and male children with ASD were 123.8 ± 15.2 and 145.8 ± 8.1 µM, respectively, and those from their unaffected brothers and sisters were 142.6 ± 10.4 and 150.8 ± 8.4 µM, respectively. There was no significant difference in taurine concentration between autistic children and their unaffected siblings. Taurine concentrations in children with ASD were also not significantly different from their parents (mothers: 139.6 ± 7.7 µM, fathers: 147.4 ± 7.5 µM). No significant difference was observed between adult controls and parents of ASD children (control females: 164.8 ± 4.8 µM, control males: 163.0 ± 7.0 µM). However, 21 out of 66 children with ASD had low taurine concentrations (<106 µM). Since taurine has anti-oxidant activity, children with ASD with low taurine concentrations will be examined for abnormal mitochondrial function. Our data imply that taurine may be a valid biomarker in a subgroup of ASD.

Telomere longitudinal shortening as a biomarker for dementia status of adults with Down syndrome.

Previous studies have suggested that Alzheimer's disease (AD) causes an accelerated shortening of telomeres, the ends of chromosomes consisting of highly conserved TTAGGG repeats that, because of unidirectional 5'-3' DNA synthesis, lose end point material with each cell division. Our own previous work suggested that telomere length of T-lymphocytes might be a remarkably accurate biomarker for "mild cognitive impairment" in adults with Down syndrome (MCI-DS), a population at dramatically high risk for AD. To verify that the progression of cognitive and functional losses due to AD produced this observed telomere shortening, we have now examined sequential changes in telomere length in five individuals with Down syndrome (3F, 2M) as they transitioned from preclinical AD to MCI-DS (N = 4) or dementia (N = 1). As in our previous studies, we used PNA (peptide nucleic acid) probes for telomeres and the chromosome 2 centromere (as an "internal standard" expected to be unaffected by aging or dementia status), with samples from the same individuals now collected prior to and following development of MCI-DS or dementia. Consistent shortening of telomere length was observed over time. Further comparisons with our previous cross-sectional findings indicated that telomere lengths prior to clinical decline were similar to those of other adults with Down syndrome (DS) who have not experienced clinical decline while telomere lengths following transition to MCI-DS or dementia in the current study were comparable to those of other adults with DS who have developed MCI-DS or dementia. Taken together, findings indicate that telomere length has significant promise as a biomarker of clinical progression of AD for adults with DS, and further longitudinal studies of a larger sample of individuals with DS are clearly warranted to validate these findings and determine if and how factors affecting AD risk also influence these measures of telomere length.

Maternal mosaicism of sex chromosome causes discordant sex chromosomal aneuploidies associated with noninvasive prenatal testing.

OBJECTIVE: To investigate the clinical efficiency of noninvasive prenatal test (NIPT) identifying fetal chromosomal aneuploidies. MATERIALS AND METHODS: In the present study, 917 women with high-risk pregnancies were invited to participate in an NIPT trial based on an Illumina HiSeq massively parallel sequencing platform. Abnormal cases in NIPT were validated by karyotyping and fluorescence in situ hybridization (FISH) analysis. All of the participants' infants were examined clinically and followed up for at least 6 months. RESULTS: A total of 35 (3.82%) high-risk pregnancies were detected with abnormal results in NIPT, which included 25 cases (2.73%) of trisomy 21 (Tri21), four cases (0.44%) of trisomy 18 (Tri18), four cases (0.44%) of Turner syndrome (45, X), one cases (0.11%) of Klinefelter's syndrome (47, XXY), and one cases (0.11%) with lower X chromosome concentration. Further validation indicated that one case of Tri18 and the case with lower X chromosome concentration were false positive results (0.22%) in NIPT. Furthermore, it was found that the false positive case with lower X chromosome concentration in NIPT was caused by maternal sex chromosomal mosaicism (45, X and 46, XX). CONCLUSION: Our findings indicated that maternal mosaicism of sex chromosome could cause discordant sex chromosomal aneuploidies associated with NIPT. We highly recommended that maternal karyotype should be confirmed for the cases with abnormal results in NIPT.

Amphiregulin Is a Critical Downstream Effector of Estrogen Signaling in ERα-Positive Breast Cancer.

Estrogen stimulation promotes epithelial cell proliferation in estrogen receptor (ERα)-positive breast cancer. Many ERα target genes have been enumerated, but the identities of the key effectors mediating the estrogen signal remain obscure. During mouse mammary gland development, the estrogen growth factor receptor (EGFR) ligand amphiregulin acts as an important stage-specific effector of estrogen signaling. In this study, we investigated the role of amphiregulin in breast cancer cell proliferation using human tissue samples and tumor xenografts in mice. Amphiregulin was enriched in ERα-positive human breast tumor cells and required for estrogen-dependent growth of MCF7 tumor xenografts. Furthermore, amphiregulin levels were suppressed in patients treated with endocrine therapy. Suppression of EGF receptor signaling appeared necessary for the therapeutic response in this setting. Our findings implicate amphiregulin as a critical mediator of the estrogen response in ERα-positive breast cancer, emphasizing the importance of EGF receptor signaling in breast tumor pathogenesis and therapeutic response.

Candidate genes for Alzheimer's disease are associated with individual differences in plasma levels of beta amyloid peptides in adults with Down syndrome.

We examined the contribution of candidates genes for Alzheimer's disease (AD) to individual differences in levels of beta amyloid peptides in adults with Down syndrom, a population at high risk for AD. Participants were 254 non-demented adults with Down syndrome, 30-78 years of age. Genomic deoxyribonucleic acid was genotyped using an Illumina GoldenGate custom array. We used linear regression to examine differences in levels of Aß peptides associated with the number of risk alleles, adjusting for age, sex, level of intellectual disability, race and/or ethnicity, and the presence of the APOE ε4 allele. For Aß42 levels, the strongest gene-wise association was found for a single nucleotide polymorphism (SNP) on CAHLM1; for Aß40 levels, the strongest gene-wise associations were found for SNPs in IDE and SOD1, while the strongest gene-wise associations with levels of the Aß42/Aß40 ratio were found for SNPs in SORCS1. Broadly classified, variants in these genes may influence amyloid precursor protein processing (CALHM1, IDE), vesicular trafficking (SORCS1), and response to oxidative stress (SOD1).

Viral Infection-Induced Differential Expression of LncRNAs Associated with Collagen in Mouse Placentas and Amniotic Sacs.

PROBLEM: We have previously determined that long non-coding RNAs (lncRNAs) are differentially expressed in preterm premature rupture of membranes (PPROM) and hypothesized that the collagenolysis ubiquitin-proteasome system may be activated by infection and inflammation. However, direct evidence of the involvement of lncRNAs in transcriptional and posttranscriptional regulation of the infection-triggered alteration of collagen is lacking. METHOD OF STUDY: A previously developed mouse model with MHV68 viral infection was assessed to determine whether viral infection may induce differential expression of lncRNAs in mouse placentas and amniotic sacs. RESULTS: Differential expression of lncRNAs that are associated with collagen was found in HMV68 viral-infected, compared to non-infected, mouse placentas and amniotic sacs. Differential expression of messenger RNAs (mRNAs) of collagen was also documented. CONCLUSIONS: Our data demonstrate, for the first time, that viral infection may induce the differential expression of lncRNAs that are associated with collagen. Based on this finding, we propose that lncRNA may have involved in regulating of infection-induced collagen transcription.

Epigenetic regulation of lncRNA connects ubiquitin-proteasome system with infection-inflammation in preterm births and preterm premature rupture of membranes.

BACKGROUND: Preterm premature rupture of membranes (PPROM) is responsible for one third of all preterm births (PTBs). We have recently demonstrated that long noncoding RNAs (lncRNAs) are differentially expressed in human placentas derived from PPROM, PTB, premature rupture of the membranes (PROM), and full-term birth (FTB), and determined the major biological pathways involved in PPROM. METHODS: Here, we further investigated the relationship of lncRNAs, which are differentially expressed in spontaneous PTB (sPTB) and PPROM placentas and are found to overlap a coding locus, with the differential expression of transcribed mRNAs at the same locus. Ten lncRNAs (five up-regulated and five down-regulated) and the lncRNA-associated 10 mRNAs (six up- and four down-regulated), which were identified by microarray in comparing PPROM vs. sPTB, were then validated by real-time quantitative PCR. RESULTS: A total of 62 (38 up- and 24 down-regulated) and 1,923 (790 up- and 1,133 down-regulated) lncRNAs were identified from placentas of premature labor (sPTB + PPROM), as compared to those from full-term labor (FTB + PROM) and from premature rupture of membranes (PPROM + PROM), as compared to those from non-rupture of membranes (sPTB + FTB), respectively. We found that a correlation existed between differentially expressed lncRNAs and their associated mRNAs, which could be grouped into four categories based on the gene strand (sense or antisense) of lncRNA and its paired transcript. These findings suggest that lncRNA regulates mRNA transcription through differential mechanisms. Differential expression of the transcripts PPP2R5C, STAM, TACC2, EML4, PAM, PDE4B, STAM, PPP2R5C, PDE4B, and EGFR indicated a co-expression among these mRNAs, which are involved in the ubiquitine-proteasome system (UPS), in addition to signaling transduction and beta adrenergic signaling, suggesting that imbalanced regulation of UPS may present an additional mechanism underlying the premature rupture of membrane in PPROM. CONCLUSION: Differentially expressed lncRNAs that were identified from the human placentas of sPTB and PPROM may regulate their associated mRNAs through differential mechanisms and connect the ubiquitin-proteasome system with infection-inflammation pathways. Although the detailed mechanisms by which lncRNAs regulate their associated mRNAs in sPTB and PPROM are yet to be clarified, our findings open a new approach to explore the pathogenesis of sPTB and PPROM.

LncRNA-regulated infection and inflammation pathways associated with pregnancy loss: genome wide differential expression of lncRNAs in early spontaneous abortion.

PROBLEM: Spontaneous abortion (SA) occurs before 20 gestational weeks. Approximately, half of recurrent SA has no identifiable cause. No report has yet been investigated the possible involvement of lncRNA in pregnancy loss. METHOD OF STUDY: Sixteen pairs of pregnancies with spontaneous abortions (SA) and induced abortions (IA) were studied. Embryonic sacs and decidua were collected for each pregnancy. A Human LncRNA Array was employed to profile genomewide lncRNAs, which were then validated by RT-PCR. RESULTS: Differentially expressed lncRNAs were identified. Biological pathways were categorized into six major groups: infection and inflammation, metabolism, signaling and transcriptional regulation, smooth muscle contraction, cell process, and coagulation. CONCLUSIONS: Infection and inflammation pathways regulated by lncRNAs were determined as the predominant pathogenetic factors underlying the SA. Finding that antisense lncRNAs have been either up- or down-regulated suggests that they may have both cis- and trans-regulations.

Na(+) /H(+) exchanger 1 (NHE1) function is necessary for maintaining mammary tissue architecture.

BACKGROUND: The mammary gland is an ideal model to study the link between form and function in normal tissue. Perhaps as interesting as the cues necessary to generate this structure are the signals required to maintain its branched architecture over the lifetime of the organism, since likely these pathways are de-regulated in malignancies. Previously, we have shown that the Na(+) /H(+) exchanger 1 (NHE1), a critical regulator of intracellular pH, was necessary for mammary branching morphogenesis. Here we provide strong evidence that NHE1 function is also necessary for maintaining mammary branched architecture. RESULTS: Inhibition of NHE1 with 5-N-Methy-N-isobutyl amiloride (MIA) on branched structures resulted in a rapid (within 24 hr) and reversible loss of branched architecture that was not accompanied by any overt changes in cell proliferation or cell death. NHE1 inhibition led to a significant acidification of intracellular pH in the branched end buds that preceded a number of events, including altered tissue polarity of myoepithelial cells, loss of NHE1 basal polarity, F-actin rearrangements, and decreased E-cadherin expression. CONCLUSIONS: Our results implicate NHE1 function and intracellular pH homeostasis as key factors that maintain mammary tissue architecture, thus, indirectly allowing for mammary function as a milk-providing (form) and -producing (function) gland.

Autoantibodies against neuronal progenitors in sera from children with autism.

The pathological role of autoantibodies in development of CNS disorders is a new idea with growing interest among neuroscientists. The involvement of autoimmune response in the pathogenesis of autism spectrum disorders (ASD) has been suggested by the presence of multiple brain-specific autoantibodies in children with ASD and in their mothers. The possibility of the effect of autoimmunity on neurogenesis and postnatal brain plasticity has not been determined. The presence of autoantibodies against human neuronal progenitor cells (NPCs) stimulated for neuronal differentiation in culture was tested in sera from children with autism (n=20) and age-matched controls (n=18) by immunoblotting and immunocytochemistry. Immunoreactivity against multiple NPCs proteins of molecular sizes of approximately 55 kDa, 105 kDa, 150 kDa, and 210 kDa in sera from individuals with autism had a higher incidence and was stronger than in control sera which immunoreacted mainly with a 150 kDa protein. The sera from children with autism immunoreacted the strongest with NPCs expressing neuronal markers Tuj1 and doublecortin, but not astrocyte marker GFAP. The epitopes recognized by antibodies from sera were not human-specific because they detected also NPCs in situ in murine hippocampus. The autoimmune reactions against NPCs suggest an impaired tolerance to neural antigens in autism. These autoantibodies may be symptomatic for autism and furthermore, their presence suggests that autoimmunity may affect postnatal neuronal plasticity particularly after impairment of blood-brain barrier. Future studies will determine the diagnostic value of the presence of autoantibodies in autism and the therapeutic value of prevention of autoimmunity in autism.

LncRNA pathway involved in premature preterm rupture of membrane (PPROM): an epigenomic approach to study the pathogenesis of reproductive disorders.

Preterm birth (PTB) is a live birth delivered before 37 weeks of gestation (GW). About one-third of PTBs result from the preterm premature rupture of membranes (PPROM). Up to the present, the pathogenic mechanisms underlying PPROM are not clearly understood. Here, we investigated the differential expression of long chain non-coding RNAs (lncRNAs) in placentas of PTBs with PPROM, and their possible involvement in the pathogenic pathways leading to PPROM. A total number of 1954, 776, and 1050 lncRNAs were identified with a microarray from placentas of PPROM (group A), which were compared to full-term birth (FTB) (group B), PTB (group C), and premature rupture of membrane (PROM) (group D) at full-term, respectively. Instead of investigating the individual pathogenic role of each lncRNA involved in the molecular mechanism underlying PPROM, we have focused on investigating the metabolic pathways and their functions to explore what is the likely association and how they are possibly involved in the development of PPROM. Six groups, including up-regulation and down-regulation in the comparisons of A vs. B, A vs. C, and A vs. D, of pathways were analyzed. Our results showed that 22 pathways were characterized as up-regulated 7 down-regulated in A vs. C, 18 up-regulated and 15 down-regulated in A vs. D, and 33 up-regulated and 7 down-regulated in A vs. B. Functional analysis showed pathways of infection and inflammatory response, ECM-receptor interactions, apoptosis, actin cytoskeleton, and smooth muscle contraction are the major pathogenic mechanisms involved in the development of PPROM. Characterization of these pathways through identification of lncRNAs opened new avenues for further investigating the epigenomic mechanisms of lncRNAs in PPROM as well as PTB.

Mild cognitive impairment identified in older individuals with Down syndrome by reduced telomere signal numbers and shorter telomeres measured in microns.

Previously, we established that short-term T lymphocyte cultures from people with Down syndrome (DS) and dementia (Alzheimer's disease) had shorter telomeres than did those from age- and sex-matched people with DS only, quantified as significantly reduced numbers of signals of peptide nucleic acid (PNA) telomere probes in whole metaphases [Jenkins et al. (2008); Neurosci Lett 440:340-343] as well as reduced telomere probe light intensity values in interphases [Jenkins et al. (2010); Neurobiol Aging 31:765-771]. We now describe shorter telomere length in adults with DS and mild cognitive impairment (MCI) compared to age- and sex-matched individuals with DS without MCI. Telomere length is quantified by reduced telomere signal numbers and shorter chromosome 1 telomeres measured in micrometers (microns). These findings were in agreement with quantitative light intensity measurements of chromosome 1 and chromosome 21 PNA telomere probes with and without the use of a "normalizing ratio" involving the fluorescence exhibited by a PNA probe for centromere 2, and with the use of light intensity measurements of interphase preparations. Most importantly, the distributions of chromosome 1 telomere lengths (in microns) were completely non-overlapping for adults with and without MCI, indicating that this measure has great promise as a biomarker for MCI as well as dementia in this population.

Ophthalmic disorders in adults with down syndrome.

A myriad of ophthalmic disorders is associated with the phenotype of Down syndrome including strabismus, cataracts, and refractive errors potentially resulting in significant visual impairment. Ophthalmic sequelae have been extensively studied in children and adolescents with Down syndrome but less often in older adults. In-depth review of medical records of older adults with Down syndrome indicated that ophthalmic disorders were common. Cataracts were the most frequent ophthalmic disorder reported, followed by refractive errors, strabismus, and presbyopia. Severity of intellectual disability was unrelated to the presence of ophthalmic disorders. Also, ophthalmic disorders were associated with lower vision-dependent functional and cognitive abilities, although not to the extent that was expected. The high prevalence of ophthalmic disorders highlights the need for periodic evaluations and individualized treatment plans for adults with Down syndrome, in general, but especially when concerns are identified.

Reduced telomere length in individuals with FMR1 premutations and full mutations.

We reported previously that 10 older men (66.4 ± 4.6 years) with premutation alleles (55-200 CGG repeats) of the FMR1 gene, with or without FXTAS, had decreased telomere length when compared to sex- and age-matched controls. Extending our use of light intensity measurements from a telomere probe hybridized to interphase preparations, we have now found shortened telomeres in 9 younger male premutation carriers (31.7 ± 17.6 years). We have also shown decreased telomere length in T lymphocytes from 6 male individuals (12.0 ± 1.8 years) with full mutation FMR1 alleles (>200 CGG repeats). These findings support our hypothesis that reduced telomere length is a component of the sub-cellular pathology of FMR1-associated disorders. The experimental approach involved pair-wise comparisons of light intensity values of 20 cells from an individual with either premutation or full mutation CGG-repeat expansions relative to an equivalent number of cells from a sex- and age-matched control. In addition, we demonstrated reduced telomere size in T-lymphocyte cultures from eight individuals with the FMR1 premutation using six different measures. Four relied on detection of light intensity differences, and two involved measuring the whole chromosome, including the telomere, in microns. This new approach confirmed our findings with light intensity measurements and demonstrated the feasibility of direct linear measurements for detecting reductions in telomere size. We have thus confirmed our hypothesis that reduced telomere length is associated with both premutation and full mutation-FMR1 alleles and have demonstrated that direct measurements of telomere length can reliably detect such reductions.

Does the cryogenic freezing process cause shorter telomeres?

We have observed evidence of increased telomere shortening in short-term T-lymphocyte cultures following freezing and thawing of the original inoculum obtained by ficoll-paque gradient centrifugation, compared to T-lymphocytes that were cultured immediately without freezing and thawing from the same blood sample from 3 female and 3 male adults. Because freezing may have similar effects on other cell types, and because telomere shortening may only manifest its effects after many years or decades, we suggest there is a pressing need for evaluation of the effects of freezing on any cells envisioned for clinical applications, including embryo implantation.

Nongenomic Mechanisms of PTEN Regulation.

A large amount of data supports the view that PTEN is a bona fide tumor suppressor gene. However, recent evidence suggests that derailment of cellular localization and expression levels of functional nonmutated PTEN is a determining force in inducing abnormal cellular and tissue outcomes. As the cellular mechanisms that regulate normal PTEN enzymatic activity resolve, it is evident that deregulation of these mechanisms can alter cellular processes and tissue architecture and ultimately lead to oncogenic transformation. Here we discuss PTEN ubiquitination, PTEN complex formation with components of the adherens junction, PTEN nuclear localization, and microRNA regulation of PTEN as essential regulatory mechanisms that determine PTEN function independent of gene mutations and epigenetic events.