Publications by authors named "David L Keefe"

91 Publications

Control of LINE-1 Expression Maintains Genome Integrity in Germline and Early Embryo Development.

Reprod Sci 2021 Jan 22. Epub 2021 Jan 22.

Department of Obstetrics and Gynecology, New York University Langone Medical Center, 462 1st Avenue, New York, NY, 10016, USA.

Maintenance of genome integrity in the germline and in preimplantation embryos is crucial for mammalian development. Epigenetic remodeling during primordial germ cell (PGC) and preimplantation embryo development may contribute to genomic instability in these cells, since DNA methylation is an important mechanism to silence retrotransposons. Long interspersed elements 1 (LINE-1 or L1) are the most common autonomous retrotransposons in mammals, corresponding to approximately 17% of the human genome. Retrotransposition events are more frequent in germ cells and in early stages of embryo development compared with somatic cells. It has been shown that L1 activation and expression occurs in germline and is essential for preimplantation development. In this review, we focus on the role of L1 retrotransposon in mouse and human germline and early embryo development and discuss the possible relationship between L1 expression and genomic instability during these stages. Although several studies have addressed L1 expression at different stages of development, the developmental consequences of this expression remain poorly understood. Future research is still needed to highlight the relationship between L1 retrotransposition events and genomic instability during germline and early embryo development.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s43032-021-00461-1DOI Listing
January 2021

Phenotypic continuum between Waardenburg syndrome and idiopathic hypogonadotropic hypogonadism in humans with SOX10 variants.

Genet Med 2021 Jan 13. Epub 2021 Jan 13.

Harvard Reproductive Sciences Center, The Reproductive Endocrine Unit and The Endocrine Unit of the Department of Medicine, Massachusetts General Hospital, Boston, MA, USA.

Purpose: SOX10 variants previously implicated in Waardenburg syndrome (WS) have now been linked to Kallmann syndrome (KS), the anosmic form of idiopathic hypogonadotropic hypogonadism (IHH). We investigated whether SOX10-associated WS and IHH represent elements of a phenotypic continuum within a unifying disorder or if they represent phenotypically distinct allelic disorders.

Methods: Exome sequencing from 1,309 IHH subjects (KS: 632; normosmic idiopathic hypogonadotropic hypogonadism [nIIHH]: 677) were reviewed for SOX10 rare sequence variants (RSVs). The genotypic and phenotypic spectrum of SOX10-related IHH (this study and literature) and SOX10-related WS cases (literature) were reviewed and compared with SOX10-RSV spectrum in gnomAD population.

Results: Thirty-seven SOX10-associated IHH cases were identified as follows: current study: 16 KS; 4 nIHH; literature: 16 KS; 1 nIHH. Twenty-three IHH cases (62%; all KS), had ≥1 known WS-associated feature(s). Moreover, five previously reported SOX10-associated WS cases showed IHH-related features. Four SOX10 missense RSVs showed allelic overlap between IHH-ascertained and WS-ascertained cases. The SOX10-HMG domain showed an enrichment of RSVs in disease states versus gnomAD.

Conclusion: SOX10 variants contribute to both anosmic (KS) and normosmic (nIHH) forms of IHH. IHH and WS represent SOX10-associated developmental defects that lie along a unifying phenotypic continuum. The SOX10-HMG domain is critical for the pathogenesis of SOX10-related human disorders.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41436-020-01051-3DOI Listing
January 2021

Telomere erosion as a placental clock: From placental pathologies to adverse pregnancy outcomes.

Placenta 2020 08 28;97:101-107. Epub 2020 Jun 28.

Department of Obstetrics and Gynecology, New York University, Langone Medical Center, New York, NY, USA.

The placenta provides nutritional and gas exchange between fetus and mother. Early in pregnancy, placental trophoblasts proliferate rapidly and invade aggressively. As pregnancy progresses, placental cells begin to age. Indeed, pregnancy itself has a tightly regulated duration, determined in large part by placental lifespan. Late in pregnancy, placental cells reach a senescent apoptotic state, activated by a number of intrinsic and extrinsic factors, including oxidative stress (OS), and DNA damage. Pregnancy complications, stillbirths and neonatal deaths have been related to OS and abnormal placental aging. Telomeres, the protective nucleoprotein structures at the ends of linear chromosomes, shorten both from cell replication and from exposure to OS. When telomeres become critically short they trigger cell cycle arrest and eventually cell death. Telomere attrition thus provide an intrinsic mechanism to explain tissue senescence and aging. Mounting evidence suggests that senescence of placental and fetal membrane cells results from telomere attrition. We review the studies that have addressed the role of telomere length (TL) in placentas from normal and complicated pregnancies, including pre-eclampsia, intrauterine growth restriction, gestational diabetes, and stillbirth. To date studies have uncovered associations between TL and a number of obstetrical complications. Future research is needed to determine whether these associations are causative, i.e. whether these clinical conditions result from telomere dysfunction, and whether particular features of telomeres, e.g. mean or shortest length, etc. could serve as clinically useful biomarkers of placental health.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.placenta.2020.06.022DOI Listing
August 2020

TCF12 haploinsufficiency causes autosomal dominant Kallmann syndrome and reveals network-level interactions between causal loci.

Hum Mol Genet 2020 Aug;29(14):2435-2450

Center for Human Disease Modeling, Duke University, Durham, NC 27701, USA.

Dysfunction of the gonadotropin-releasing hormone (GnRH) axis causes a range of reproductive phenotypes resulting from defects in the specification, migration and/or function of GnRH neurons. To identify additional molecular components of this system, we initiated a systematic genetic interrogation of families with isolated GnRH deficiency (IGD). Here, we report 13 families (12 autosomal dominant and one autosomal recessive) with an anosmic form of IGD (Kallmann syndrome) with loss-of-function mutations in TCF12, a locus also known to cause syndromic and non-syndromic craniosynostosis. We show that loss of tcf12 in zebrafish larvae perturbs GnRH neuronal patterning with concomitant attenuation of the orthologous expression of tcf3a/b, encoding a binding partner of TCF12, and stub1, a gene that is both mutated in other syndromic forms of IGD and maps to a TCF12 affinity network. Finally, we report that restored STUB1 mRNA rescues loss of tcf12 in vivo. Our data extend the mutational landscape of IGD, highlight the genetic links between craniofacial patterning and GnRH dysfunction and begin to assemble the functional network that regulates the development of the GnRH axis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/hmg/ddaa120DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7608740PMC
August 2020

Characteristics and Outcomes of 241 Births to Women With Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection at Five New York City Medical Centers.

Obstet Gynecol 2020 08;136(2):273-282

Department of Obstetrics & Gynecology and Women's Health, Montefiore Medical Center & Albert Einstein College of Medicine, Bronx, the Department of Obstetrics, Gynecology and Reproductive Science, Mount Sinai Health System & Icahn School of Medicine at Mount Sinai, New York, the Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, Columbia University Irving Medical Center, NewYork-Presbyterian Hospital, New York, the Department of Obstetrics and Gynecology, NYU Langone Health & NYU Grossman School of Medicine, New York, the Department of Epidemiology & Population Health, Albert Einstein College of Medicine, Bronx, and the Department of Obstetrics and Gynecology, NYC Health and Hospitals-Elmhurst, Elmhurst, New York.

Objective: To describe the characteristics and birth outcomes of women with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection as community spread in New York City was detected in March 2020.

Methods: We performed a prospective cohort study of pregnant women with laboratory-confirmed SARS-CoV-2 infection who gave birth from March 13 to April 12, 2020, identified at five New York City medical centers. Demographic and clinical data from delivery hospitalization records were collected, and follow-up was completed on April 20, 2020.

Results: Among this cohort (241 women), using evolving criteria for testing, 61.4% of women were asymptomatic for coronavirus disease 2019 (COVID-19) at the time of admission. Throughout the delivery hospitalization, 26.5% of women met World Health Organization criteria for mild COVID-19, 26.1% for severe, and 5% for critical. Cesarean birth was the mode of delivery for 52.4% of women with severe and 91.7% with critical COVID-19. The singleton preterm birth rate was 14.6%. Admission to the intensive care unit was reported for 17 women (7.1%), and nine (3.7%) were intubated during their delivery hospitalization. There were no maternal deaths. Body mass index (BMI) 30 or higher was associated with COVID-19 severity (P=.001). Nearly all newborns tested negative for SARS-CoV-2 infection immediately after birth (97.5%).

Conclusion: During the first month of the SARS-CoV-2 outbreak in New York City and with evolving testing criteria, most women with laboratory-confirmed infection admitted for delivery did not have symptoms of COVID-19. Almost one third of women who were asymptomatic on admission became symptomatic during their delivery hospitalization. Obesity was associated with COVID-19 severity. Disease severity was associated with higher rates of cesarean and preterm birth.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/AOG.0000000000004025DOI Listing
August 2020

Impaired reproductive function and fertility preservation in a woman with a dyskeratosis congenita.

J Assist Reprod Genet 2020 May 13;37(5):1221-1225. Epub 2020 May 13.

Department of Obstetrics and Gynecology, New York University Langone Health, 550 First Avenue, NBV-9N1A, New York, NY, 10016, USA.

Purpose: To determine the impact of accelerated telomere shortening on the fertility parameters and treatment outcomes of a woman with dyskeratosis congenita (DKC).

Methods: A case study of the clinical data, blood, discarded oocytes, and arrested embryos of a woman with DKC and donated cryopreserved embryos from unaffected patients. Mean telomere length in blood cells was analyzed by flow cytometry-fluorescence in situ hybridization (flow-FISH) and qPCR. The load of short telomeres in blood cells was measured by universal single telomere length analysis (Universal STELA). The mean telomere length in embryos was analyzed by single-cell amplification of telomere repeats (SCATR) PCR.

Results: Comparison of clinical parameters revealed that the DKC patient had reduced anti-Mullerian hormone (0.3 vs 4.1 ± 5.7 ng/ML), reduced oocytes retrieved (7 vs 18.5 ± 9.5), reduced fertilization rate, and reduced euploidy rate relative to unaffected patients. Additionally, mean telomere length in DKC embryos were shorter than unaffected embryos. However, hormone treatment led to increased leukocyte telomere length, while the load of short telomeres was also shown to decrease during the course of treatment.

Conclusions: We demonstrate for the first time the direct detrimental impacts of short telomeres on female fertility. We further demonstrate positive effects of hormone treatments for people with telomere disorders.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10815-020-01758-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7244669PMC
May 2020

Telomere Length and Telomerase Activity in Immature Oocytes and Cumulus Cells of Women with Polycystic Ovary Syndrome.

Reprod Sci 2020 06 6;27(6):1293-1303. Epub 2020 Jan 6.

Department of Gynecology and Obstetrics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, 14049-900, Brazil.

Metaphase II oocytes (MII) from polycystic ovary syndrome (PCOS) frequently have impaired oocyte competence. Since telomere maintenance is important for folliculogenesis, oocyte maturation, and early embryonic development, we sought to verify the implications of PCOS on telomere length and telomerase activity in immature oocytes and cumulus cells. 43 PCOS and 67 control women were included, and anthropometric, biochemical, and hormonal characteristics were evaluated. The telomere length in germinal vesicle stage (GV) and in metaphase I (MI) oocytes, as well as in the cumulus cells of immature (CCI) and mature oocytes (CCM), and in leukocytes was measured by qPCR. The telomerase activity in reproductive cells was evaluated by the TRAPeze® XL Kit. The body mass index (p = 0.001), LH (p = 0.015), estradiol (p = 0.004), insulin (p = 0.002), testosterone (p < 0.0001), androstenedione (p = 0.001), free androgen index (p < 0.0001), and c-reactive protein (p = 0.003) were greater, while the FSH (p = 0.0002) was lower in the PCOS group. The telomere length in the CCI (p = 0.649) and CCM (p = 0.378) did not differ between the PCOS and the control groups. On the other hand, telomerase activity in the CCI (p = 0.003) and CCM (p = 0.022) was higher in the PCOS group. In the leukocyte's cells, the telomere length was reduced in the PCOS group (p = 0.025). In the GV and MI oocytes, no differences were observed in telomere length and telomerase activity between the groups. We showed that telomere length is not altered in reproductive cells from PCOS. However, higher telomerase activity in the CCI and CCM may be required for telomere length maintenance.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s43032-019-00120-6DOI Listing
June 2020

Widespread Transcriptional Scanning in the Testis Modulates Gene Evolution Rates.

Cell 2020 01;180(2):248-262.e21

Institute for Computational Medicine, NYU Langone Health, New York, NY 10016, USA; Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY 10016, USA. Electronic address:

The testis expresses the largest number of genes of any mammalian organ, a finding that has long puzzled molecular biologists. Our single-cell transcriptomic data of human and mouse spermatogenesis provide evidence that this widespread transcription maintains DNA sequence integrity in the male germline by correcting DNA damage through a mechanism we term transcriptional scanning. We find that genes expressed during spermatogenesis display lower mutation rates on the transcribed strand and have low diversity in the population. Moreover, this effect is fine-tuned by the level of gene expression during spermatogenesis. The unexpressed genes, which in our model do not benefit from transcriptional scanning, diverge faster over evolutionary timescales and are enriched for sensory and immune-defense functions. Collectively, we propose that transcriptional scanning shapes germline mutation signatures and modulates mutation rates in a gene-specific manner, maintaining DNA sequence integrity for the bulk of genes but allowing for faster evolution in a specific subset.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cell.2019.12.015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7891839PMC
January 2020

Gli3 Regulates Vomeronasal Neurogenesis, Olfactory Ensheathing Cell Formation, and GnRH-1 Neuronal Migration.

J Neurosci 2020 01 25;40(2):311-326. Epub 2019 Nov 25.

Department of Biological Sciences; The RNA Institute, and the Center for Neuroscience Research; University at Albany, State University of New York, Albany, New York 12222, and

During mammalian development, gonadotropin-releasing-hormone-1 neurons (GnRH-1ns) migrate from the developing vomeronasal organ (VNO) into the brain asserting control of pubertal onset and fertility. Recent data suggest that correct development of the olfactory ensheathing cells (OEC) is imperative for normal GnRH-1 neuronal migration. However, the full ensemble of molecular pathways that regulate OEC development remains to be fully deciphered. Loss-of-function of the transcription factor Gli3 is known to disrupt olfactory development, however, if Gli3 plays a role in GnRH-1 neuronal development is unclear. By analyzing Gli3 extra-toe mutants (Gli3), we found that Gli3 loss-of-function compromises the onset of achaete-scute family bHLH transcription factor 1 (Ascl-1) vomeronasal progenitors and the formation of OEC in the nasal mucosa. Surprisingly, GnRH-1 neurogenesis was intact in Gli3 mice but they displayed significant defects in GnRH-1 neuronal migration. In contrast, Ascl-1 mutants showed reduced neurogenesis for both vomeronasal and GnRH-1ns but less severe defects in OEC development. These observations suggest that Gli3 is critical for OEC development in the nasal mucosa and subsequent GnRH-1 neuronal migration. However, the nonoverlapping phenotypes between Ascl-1 and Gli3 mutants indicate that Ascl-1, while crucial for GnRH-1 neurogenesis, is not required for normal OEC development. Because Kallmann syndrome (KS) is characterized by abnormal GnRH-1ns migration, we examined whole-exome sequencing data from KS subjects. We identified and validated a loss-of-function variant in a KS individual. These findings provide new insights into GnRH-1 and OECs development and demonstrate that human mutations contribute to KS etiology. The transcription factor Gli3 is necessary for correct development of the olfactory system. However, if Gli3 plays a role in controlling GnRH-1 neuronal development has not been addressed. We found that Gli3 loss-of-function compromises the onset of Ascl-1 vomeronasal progenitors, formation of olfactory ensheathing cells in the nasal mucosa, and impairs GnRH-1 neuronal migration to the brain. By analyzing Ascl-1 mutants we dissociated the neurogenic defects observed in Gli3 mutants from lack of olfactory ensheathing cells in the nasal mucosa, moreover, we discovered that Ascl-1 is necessary for GnRH-1 ontogeny. Analyzing human whole-exome sequencing data, we identified a loss-of-function variant in a KS individual. Our data suggest that is a candidate gene contributing to KS etiology.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1523/JNEUROSCI.1977-19.2019DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6948949PMC
January 2020

Epigenetics and Female Reproductive Aging.

Front Endocrinol (Lausanne) 2019 29;10:473. Epub 2019 Aug 29.

Department of Obstetrics and Gynecology, New York University School of Medicine, New York, NY, United States.

With more women than ever waiting until a more advanced age to have children, there exists a newfound urgency to identify the various implications aging has on human reproduction, and understand the disrupted biological processes that result in these changes. In this review, we focus on one recent area of study: the age related epigenetic changes that have been found in female reproductive organs, and the effect these changes may contribute to reproductive outcomes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fendo.2019.00473DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6736555PMC
August 2019

Easing US restrictions on mitochondrial replacement therapy would protect research interests but grease the slippery slope.

Authors:
David L Keefe

J Assist Reprod Genet 2019 Sep 28;36(9):1781-1785. Epub 2019 Aug 28.

Department of Obstetrics and Gynecology, NYU Langone Health, 550 First Avenue, BV-9N1A, New York, NY, 10016, USA.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10815-019-01529-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6730721PMC
September 2019

Proceedings of the New York University School of Medicine Reproductive Ethics Conference: Challenges and Solutions.

J Assist Reprod Genet 2019 Sep 25;36(9):1767-1769. Epub 2019 Jul 25.

Department of Obstetrics and Gynecology, NYU Langone Medical Center, 550 First Avenue, NBV 9N1-C, New York, NY, 10016, USA.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10815-019-01522-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6730970PMC
September 2019

Telomeres and genomic instability during early development.

Authors:
David L Keefe

Eur J Med Genet 2020 Feb 9;63(2):103638. Epub 2019 Mar 9.

Department of Ob/Gyn, NYU Langone Medical Center, 550 First Avenue, NBV 9N1A, New York, 10012, New York, USA. Electronic address:

Genomic instability is widespread during early embryo development. Aneuploidy, mosaicism, and copy number variants (CNVs) commonly appear in human preimplantation embryos. Both age-dependent meiotic aneuploidy and age-independent mitotic aneuploidy and CNVs occur In human embryos. Telomere attrition, which contributes to genomic instability in somatic cells, also may promote genomic instability in preimplantation embryos. Telomere dynamics during gametogenesis are strikingly dimorphic between females and males. Sperm telomeres lengthen with advancing paternal age, while oocyte telomeres are among the shortest in the body. Spermatogonia express telomerase activity throughout the life of the male, while oocytes and cleavage stage embryos express low or un-measureable levels of telomerase activity. Telomere attrition in oocytes contributes to meiotic dysfunction, including spindle dysmorphologies, reduced synapsis and chiasmata, as well as delayed, arrested and fragmented embryos. Cleavage stage embryos, with such inefficient telomere reconstitution, likely undergo NHEJ, which produces anaphase lag, chromosome bridges, micronuclei, and genomic instability, including mosaicism and CNVs. Cleavage stage embryos reconstitute the short telomeres inherited from their mothers by Alternative Lengthening of Telomeres (ALT), a DNA recombination based method involving RAD 50, MRE 11, Werner and Bloom proteins, as well as telomere sister chromatid exchange. ALT robustly reconstitutes telomeres, but also predisposes to genomic instability.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ejmg.2019.03.002DOI Listing
February 2020

Uterus transplantation in women who are genetically XY.

J Med Ethics 2019 10 25;45(10):687-689. Epub 2019 Feb 25.

Department of Obstetrics and Gynecology, New York University School of Medicine, New York City, New York, USA.

Uterus transplantation is an emerging technology adding to the arsenal of treatments for infertility; specifically the only available treatment for uterine factor infertility. Ethical investigations concerning risks to uteri donors and transplant recipients have been discussed in the literature. However, missing from the discourse is the potential of uterus transplantation in other groups of genetically XY women who experience uterine factor infertility. There have been philosophical inquiries concerning uterus transplantation in genetically XY women, which includes transgender women and women with complete androgen insufficiency syndrome. We discuss the potential medical steps necessary and associated risks for uterus transplantation in genetically XY women. Presently, the medical technology does not exist to make uterus transplantation a safe and effective option for genetically XY women, however this group should not be summarily excluded from participation in trials. Laboratory research is needed to better understand and reduce medical risk and widen the field to all women who face uterine factor infertility.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1136/medethics-2018-105222DOI Listing
October 2019

Uroplakins play conserved roles in egg fertilization and acquired additional urothelial functions during mammalian divergence.

Mol Biol Cell 2018 12 10;29(26):3128-3143. Epub 2018 Oct 10.

Department of Cell Biology, New York University School of Medicine, New York, NY 10016.

Uroplakin (UP) tetraspanins and their associated proteins are major mammalian urothelial differentiation products that form unique two-dimensional crystals of 16-nm particles ("urothelial plaques") covering the apical urothelial surface. Although uroplakins are highly expressed only in mammalian urothelium and are often referred to as being urothelium specific, they are also expressed in several mouse nonurothelial cell types in stomach, kidney, prostate, epididymis, testis/sperms, and ovary/oocytes. In oocytes, uroplakins colocalize with CD9 on cell-surface and multivesicular body-derived exosomes, and the cytoplasmic tail of UPIIIa undergoes a conserved fertilization-dependent, Fyn-mediated tyrosine phosphorylation that also occurs in eggs. Uroplakin knockout and antibody blocking reduce mouse eggs' fertilization rate in in vitro fertilization assays, and UPII/IIIa double-knockout mice have a smaller litter size. Phylogenetic analyses showed that uroplakin sequences underwent significant mammal-specific changes. These results suggest that, by mediating signal transduction and modulating membrane stability that do not require two-dimensional-crystal formation, uroplakins can perform conserved and more ancestral fertilization functions in mouse and frog eggs. Uroplakins acquired the ability to form two-dimensional-crystalline plaques during mammalian divergence, enabling them to perform additional functions, including umbrella cell enlargement and the formation of permeability and mechanical barriers, to protect/modify the apical surface of the modern-day mammalian urothelium.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1091/mbc.E18-08-0496DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6340209PMC
December 2018

Telomere length and early trauma in schizophrenia.

Schizophr Res 2018 09 2;199:426-430. Epub 2018 Apr 2.

Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA. Electronic address:

Background: Childhood trauma is emerging as a risk factor for schizophrenia, but its mechanism with respect to etiology is unknown. One possible pathway is through leucocyte telomere length (LTL) shortening, a measure of cellular aging associated with trauma. This study examined early trauma and LTL shortening in schizophrenia and considered sex effects.

Methods: The early trauma inventory (ETI) was administered to 48 adults with DSM-5 schizophrenia and 18 comparison participants. LTL was measured using qPCR.

Outcomes: Cases had significantly more global trauma (F=4.10, p<0.01) and traumatic events (F=11.23, p<0.001), but case and control groups had similar LTL (1.91±0.74 and 1.83±0.62: p=0.68). The association of early trauma and LTL differed by sex in cases and controls (Fisher's R: Z<0.05). Significant negative associations were shown in male cases and, conversely, in female controls. For example, physical punishment was associated LTL shortening in males' cases (r=-0.429, p<01). Only female controls showed significant telomere shortening in association with early trauma.

Interpretation: This data confirms the substantial excess of early trauma among schizophrenia cases. There were significant sex-differences in the relationship of the trauma to LTL, with only male cases showing the expected shortening. There were converse sex effects in the control group. Mean LTL was notably similar in cases and controls, despite the trauma-related shortening in male cases, cigarette smoking, older age and chronic illness of the cases. Factors may lengthen LTL in some schizophrenia cases. The converse sex differences in the cases are consistent with findings defective sexual differentiation in schizophrenia, consistent with other findings in the field.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.schres.2018.02.059DOI Listing
September 2018

Contemporary Hormonal Contraception and the Risk of Breast Cancer.

N Engl J Med 2018 03;378(13):1265

New York University School of Medicine, New York, NY

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1056/NEJMc1800054DOI Listing
March 2018

Reconstitution of ovarian function following transplantation of primordial germ cells.

Sci Rep 2017 05 3;7(1):1427. Epub 2017 May 3.

State Key Laboratory of Medicinal Chemical Biology, Department of Cell Biology and Genetics, College of Life Sciences, Nankai University, Tianjin, 300071, China.

Ovarian aging occurs earlier than somatic aging. We tested the hypothesis that ovarian functions could be artificially reconstructed by transplantation of primordial germ cells (PGCs). We compared various methods for transplantation of PGCs aggregated with gonadal somatic cells and showed that reconstituted ovaries exhibited folliculogenesis after transplantation of PGCs-aggregates into either kidney capsule or ovarian bursa. Neo-oogenesis occurred early after transplantation, as evidenced by the presence of prophase I meiocytes displaying homologous pairing. Moreover, endocrine function was recovered in ovariectomized recipients, including elevated levels of AMH and estradiol. Interestingly, folliculogenesis in the reconstituted ovaries failed to sustain past four weeks. Regardless of transplantation method, follicles diminished after 45 days, accompanied by increased apoptosis, and were undetectable after two months. Meanwhile, no replicative PGCs or prophase I meiocytes could be found. Together, transplantation of PGCs can effectively reconstitute ovarian functions but for limited time. These data suggest that PGCs do not undergo self-renewal but rapidly enter meiosis following transplantation. Global activation of primordial follicles in artificial ovaries can result in further rapid loss of germ cells. Methods for maintaining self-renewal and expansion in vivo of PGCs and controlling follicle activation will be essential for continuing maintenance of the functional reconstructed ovaries.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-017-01648-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5431110PMC
May 2017

mTORC1/2 inhibition preserves ovarian function and fertility during genotoxic chemotherapy.

Proc Natl Acad Sci U S A 2017 03 7;114(12):3186-3191. Epub 2017 Mar 7.

Department of Microbiology, New York University School of Medicine, New York, NY 10016;

The ovary contains oocytes within immature (primordial) follicles that are fixed in number at birth. Activation of follicles within this fixed pool causes an irreversible decline in reproductive capacity, known as the ovarian reserve, until menopause. Premenopausal women undergoing commonly used genotoxic (DNA-damaging) chemotherapy experience an accelerated loss of the ovarian reserve, leading to subfertility and infertility. Therefore, there is considerable interest but little effective progress in preserving ovarian function during chemotherapy. Here we show that blocking the kinase mammalian/mechanistic target of rapamycin (mTOR) with clinically available small-molecule inhibitors preserves ovarian function and fertility during chemotherapy. Using a clinically relevant mouse model of chemotherapy-induced gonadotoxicity by cyclophosphamide, and inhibition of mTOR complex 1 (mTORC1) with the clinically approved drug everolimus (RAD001) or inhibition of mTORC1/2 with the experimental drug INK128, we show that mTOR inhibition preserves the ovarian reserve, primordial follicle counts, serum anti-Mullerian hormone levels (a rigorous measure of the ovarian reserve), and fertility. Chemotherapy-treated animals had significantly fewer offspring compared with all other treatment groups, whereas cotreatment with mTOR inhibitors preserved normal fertility. Inhibition of mTORC1 or mTORC1/2 within ovaries was achieved during chemotherapy cotreatment, concomitant with preservation of primordial follicle counts. Importantly, our findings indicate that as little as a two- to fourfold reduction in mTOR activity preserves ovarian function and normal birth numbers. As everolimus is approved for tamoxifen-resistant or relapsing estrogen receptor-positive breast cancer, these findings represent a potentially effective and readily accessible pharmacologic approach to fertility preservation during conventional chemotherapy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1073/pnas.1617233114DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5373380PMC
March 2017

Telomeres, Reproductive Aging, and Genomic Instability During Early Development.

Authors:
David L Keefe

Reprod Sci 2016 12;23(12):1612-1615

Department of Obstetrics and Gynecology, NYU Langone Medical Center, New York, NY, USA

Implantation rate decreases and miscarriage rate increases with advancing maternal age. The oocyte must be the locus of reproductive aging because donation of oocytes from younger to older women abrogates the effects of aging on fecundity. Nuclear transfer experiments in a mouse model of reproductive aging show that the reproductive aging phenotype segregates with the nucleus rather than the cytoplasm. A number of factors within the nucleus have been hypothesized to mediate reproductive aging, including disruption of cohesions, reduced chiasma, aneuploidy, disrupted meiotic spindles, and DNA damage caused by chronic exposure to reactive oxygen species. We have proposed telomere attrition as a parsimonious way to explain these diverse effects of aging on oocyte function. Telomeres are repetitive sequences of DNA and associated proteins, which form a loop (t loop) at chromosome ends. Telomeres prevent the blunt end of DNA from triggering a DNA damage response. Previously, we showed that experimental telomere shortening phenocopies reproductive aging in mice. Telomere shortening causes reduced synapsis and chiasma, chromosome fusions, embryo arrest and fragmentation, and abnormal meiotic spindles. Telomere length of polar bodies predicts the fragmentation of human embryos. Telomerase, the reverse transcriptase capable of reconstituting shortened telomeres, is only minimally active in oocytes and preimplantation embryos. Intriguingly, during the first cell cycles following activation, telomeres robustly elongate via a DNA double-strand break mechanism called alternative lengthening of telomeres (ALTs). Alternative lengthening of telomere takes place even in telomerase-null mice. This mechanism of telomere elongation previously had been found only in cancer cells lacking telomerase activity. We propose that ALT elongates telomeres across generations but does so at the cost of extensive genomic instability in preimplantation embryos.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/1933719116676397DOI Listing
December 2016

Tet Enzymes Regulate Telomere Maintenance and Chromosomal Stability of Mouse ESCs.

Cell Rep 2016 05 12;15(8):1809-21. Epub 2016 May 12.

State Key Laboratory of Medicinal Chemical Biology, Department of Cell Biology and Genetics, College of Life Sciences, Nankai University, Tianjin 300071, China; Collaborative Innovation Center for Biotherapy, West China Hospital, Chengdu 610041, China. Electronic address:

Ten-eleven translocation (Tet) family proteins convert 5-methylcytosine to 5-hydroxymethylcytosine. We show that mouse embryonic stem cells (ESCs) depleted of Tet1 and/or Tet2 by RNAi exhibit short telomeres and chromosomal instability, concomitant with reduced telomere recombination. Tet1 and Tet2 double-knockout ESCs also display short telomeres but to a lesser extent. Notably, Tet1/2/3 triple-knockout ESCs show heterogeneous telomere lengths and increased frequency of telomere loss and chromosomal fusion. Mechanistically, Tets depletion or deficiency increases Dnmt3b and decreases 5hmC levels, resulting in elevated methylation levels at sub-telomeres. Consistently, knockdown of Dnmt3b or addition of 2i (MAPK and GSK3β inhibitors), which also inhibits Dnmt3b, reduces telomere shortening, partially rescuing Tet1/2 deficiency. Interestingly, Tet1/2 double or Tet1/2/3 triple knockout in ESCs consistently upregulates Zscan4, which may counteract telomere shortening. Together, Tet enzymes play important roles in telomere maintenance and chromosomal stability of ESCs by modulating sub-telomeric methylation levels.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.celrep.2016.04.058DOI Listing
May 2016

A single-cell assay for telomere DNA content shows increasing telomere length heterogeneity, as well as increasing mean telomere length in human spermatozoa with advancing age.

J Assist Reprod Genet 2015 Nov 28;32(11):1685-90. Epub 2015 Sep 28.

Department of Obstetrics and Gynecology, New York University, Langone Medical Center, New York, NY, 10016, USA.

Purpose: The effect of age on telomere length heterogeneity in men has not been studied previously. Our aims were to determine the relationship between variation in sperm telomere length (STL), men's age, and semen parameters in spermatozoa from men undergoing in vitro fertilization (IVF) treatment.

Methods: To perform this prospective cross-sectional pilot study, telomere length was estimated in 200 individual spermatozoa from men undergoing IVF treatment at the NYU Fertility Center. A novel single-cell telomere content assay (SCT-pqPCR) measured telomere length in individual spermatozoa.

Results: Telomere length among individual spermatozoa within an ejaculate varies markedly and increases with age. Older men not only have longer STL but also have more variable STL compared to younger men. STL from samples with normal semen parameters was significantly longer than that from samples with abnormal parameters, but STL did not differ between spermatozoa with normal versus abnormal morphology.

Conclusion: The marked increase in STL heterogeneity as men age is consistent with a role for ALT during spermatogenesis. No data have yet reported the effect of age on STL heterogeneity. Based on these results, future studies should expand this modest sample size to search for molecular evidence of ALT in human testes during spermatogenesis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10815-015-0574-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4651947PMC
November 2015

Increased DNA damage and repair deficiency in granulosa cells are associated with ovarian aging in rhesus monkey.

J Assist Reprod Genet 2015 Jul 10;32(7):1069-78. Epub 2015 May 10.

State Key Laboratory of Medicinal Chemical Biology; Collaborative Innovation Center for Biotherapy, College of Life Sciences, Nankai University, Tianjin, 300071, China.

Purpose: Ovarian aging is closely tied to the decline in ovarian follicular reserve and oocyte quality. During the prolonged reproductive lifespan of the female, granulosa cells connected with oocytes play critical roles in maintaining follicle reservoir, oocyte growth and follicular development. We tested whether double-strand breaks (DSBs) and repair in granulosa cells within the follicular reservoir are associated with ovarian aging.

Methods: Ovaries were sectioned and processed for epi-fluorescence microscopy, confocal microscopy, and immunohistochemistry. DNA damage was revealed by immunstaining of γH2AX foci and telomere damage by γH2AX foci co-localized with telomere associated protein TRF2. DNA repair was indicated by BRCA1 immunofluorescence.

Results: DSBs in granulosa cells increase and DSB repair ability, characterized by BRCA1 foci, decreases with advancing age. γH2AX foci increase in primordial, primary and secondary follicles with advancing age. Likewise, telomere damage increases with advancing age. In contrast, BRCA1 foci in granulosa cells of primordial, primary and secondary follicles decrease with monkey age. BRCA1 positive foci in the oocyte nuclei also decline with maternal age.

Conclusions: Increased DSBs and reduced DNA repair in granulosa cells may contribute to ovarian aging. Discovery of therapeutics that targets these pathways might help maintain follicle reserve and postpone ovarian dysfunction with age.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10815-015-0483-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4531862PMC
July 2015

Telomere length variability is related to symptoms and cognition in schizophrenia.

Schizophr Res 2015 May 1;164(1-3):268-9. Epub 2015 Apr 1.

Institute for Social and Psychiatric Initiatives (InSPIRES), Department of Psychiatry, New York University School of Medicine, New York, NY, USA; Department of Psychiatry, New York University School of Medicine, New York, NY, USA.; Creedmoor Psychiatric Center, NY State Office of Mental Health, Queens Village, NY 11427, USA.. Electronic address:

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.schres.2015.03.011DOI Listing
May 2015

Inflammatory biomarkers and telomere length in women with polycystic ovary syndrome.

Fertil Steril 2015 Feb 20;103(2):542-7.e2. Epub 2014 Nov 20.

Department of Obstetrics and Gynecology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil. Electronic address:

Objective: To analyze whether leukocyte telomere length (LTL) is impaired in women with polycystic ovary syndrome (PCOS).

Design: Case-control study.

Setting: Hospital.

Patient(s): A total of 274 women, including 150 patients with PCOS and 124 controls.

Intervention(s): None.

Main Outcome Measure(s): Body mass index (BMI), waist circumference, systemic arterial pressure, lipid profile, E(2), LH, T, androstenedione, PRL, TSH, sex hormone-binding globulin, C-reactive protein (CRP), homocysteine, free androgen index, and the homeostatic model of insulin sensitivity (HOMA-IR) index were analyzed. The LTL evaluation was measured by quantitative polymerase chain reaction.

Result(s): The PCOS group had higher values for weight, BMI, waist circumference, systolic arterial pressure, triglycerides, LH, T, insulin, CRP, free androgen index, and HOMA-IR compared with the control group. Sex hormone-binding globulin and E(2) levels were lower in the PCOS group than in the control group. The LTL did not differ between groups. Age, BMI, and HOMA-IR had no significant effect on LTL. The inflammatory biomarkers CRP and homocysteine were negatively correlated with LTL in patients with PCOS.

Conclusion(s): Our results showed no differences in LTL between patients with PCOS and controls, but CRP and homocysteine biomarkers negatively correlated with LTL in the PCOS group.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.fertnstert.2014.10.035DOI Listing
February 2015

Telomere elongation and naive pluripotent stem cells achieved from telomerase haplo-insufficient cells by somatic cell nuclear transfer.

Cell Rep 2014 Dec 20;9(5):1603-1609. Epub 2014 Nov 20.

Center for Advanced Models for Translational Sciences and Therapeutics, University of Michigan Medical Center, Ann Arbor, MI 48109, USA. Electronic address:

Haplo-insufficiency of telomerase genes in humans leads to telomere syndromes such as dyskeratosis congenital and idiopathic pulmonary fibrosis. Generation of pluripotent stem cells from telomerase haplo-insufficient donor cells would provide unique opportunities toward the realization of patient-specific stem cell therapies. Recently, pluripotent human embryonic stem cells (ntESCs) have been efficiently achieved by somatic cell nuclear transfer (SCNT). We tested the hypothesis that SCNT could effectively elongate shortening telomeres of telomerase haplo-insufficient cells in the ntESCs with relevant mouse models. Indeed, telomeres of telomerase haplo-insufficient (Terc(+/-)) mouse cells are elongated in ntESCs. Moreover, ntESCs derived from Terc(+/-) cells exhibit naive pluripotency as evidenced by generation of Terc(+/-) ntESC clone pups by tetraploid embryo complementation, the most stringent test of naive pluripotency. These data suggest that SCNT could offer a powerful tool to reprogram telomeres and to discover the factors for robust restoration of telomeres and pluripotency of telomerase haplo-insufficient somatic cells.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.celrep.2014.10.052DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4268138PMC
December 2014

In every end there is a beginning--telomeres in male reproduction.

Authors:
David L Keefe

Fertil Steril 2014 Sep 6;102(3):690-1. Epub 2014 Aug 6.

New York University Langone Medical Center, New York, New York.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.fertnstert.2014.07.1236DOI Listing
September 2014

Rif1 maintains telomere length homeostasis of ESCs by mediating heterochromatin silencing.

Dev Cell 2014 Apr;29(1):7-19

State Key Laboratory of Medicinal Chemical Biology, Department of Cell Biology and Genetics, College of Life Sciences, Nankai University, Tianjin 300071, China. Electronic address:

Telomere length homeostasis is essential for genomic stability and unlimited self-renewal of embryonic stem cells (ESCs). We show that telomere-associated protein Rif1 is required to maintain telomere length homeostasis by negatively regulating Zscan4 expression, a critical factor for telomere elongation by recombination. Depletion of Rif1 results in terminal hyperrecombination, telomere length heterogeneity, and chromosomal fusions. Reduction of Zscan4 by shRNA significantly rescues telomere recombination defects of Rif1-depleted ESCs and associated embryonic lethality. Further, Rif1 negatively modulates Zscan4 expression by maintaining H3K9me3 levels at subtelomeric regions. Mechanistically, Rif1 interacts and stabilizes H3K9 methylation complex. Thus, Rif1 regulates telomere length homeostasis of ESCs by mediating heterochromatic silencing.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.devcel.2014.03.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4720134PMC
April 2014

No evidence for neo-oogenesis may link to ovarian senescence in adult monkey.

Stem Cells 2013 Nov;31(11):2538-50

State Key Laboratory of Medicinal Chemical Biology, The 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics and College of Life Sciences, Nankai University, Tianjin, China; Key Laboratory of Ministry of Health on Hormones and Development, Metabolic Diseases Hospital, Tianjin Medical University, Tianjin, China.

Female germline or oogonial stem cells transiently residing in fetal ovaries are analogous to the spermatogonial stem cells or germline stem cells (GSCs) in adult testes where GSCs and meiosis continuously renew. Oocytes can be generated in vitro from embryonic stem cells and induced pluripotent stem cells, but the existence of GSCs and neo-oogenesis in adult mammalian ovaries is less clear. Preliminary findings of GSCs and neo-oogenesis in mice and humans have not been consistently reproducible. Monkeys provide the most relevant model of human ovarian biology. We searched for GSCs and neo-meiosis in ovaries of adult monkeys at various ages, and compared them with GSCs from adult monkey testis, which are characterized by cytoplasmic staining for the germ cell marker DAZL and nuclear expression of the proliferative markers PCNA and KI67, and pluripotency-associated genes LIN28 and SOX2, and lack of nuclear LAMIN A, a marker for cell differentiation. Early meiocytes undergo homologous pairing at prophase I distinguished by synaptonemal complex lateral filaments with telomere perinuclear distribution. By exhaustive searching using comprehensive experimental approaches, we show that proliferative GSCs and neo-meiocytes by these specific criteria were undetectable in adult mouse and monkey ovaries. However, we found proliferative nongermline somatic stem cells that do not express LAMIN A and germ cell markers in the adult ovaries, notably in the cortex and granulosa cells of growing follicles. These data support the paradigm that adult ovaries do not undergo germ cell renewal, which may contribute significantly to ovarian senescence that occurs with age.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/stem.1480DOI Listing
November 2013

Robust measurement of telomere length in single cells.

Proc Natl Acad Sci U S A 2013 May 9;110(21):E1906-12. Epub 2013 May 9.

Department of Obstetrics and Gynecology, New York University Langone Medical Center, NY 10016, USA.

Measurement of telomere length currently requires a large population of cells, which masks telomere length heterogeneity in single cells, or requires FISH in metaphase arrested cells, posing technical challenges. A practical method for measuring telomere length in single cells has been lacking. We established a simple and robust approach for single-cell telomere length measurement (SCT-pqPCR). We first optimized a multiplex preamplification specific for telomeres and reference genes from individual cells, such that the amplicon provides a consistent ratio (T/R) of telomeres (T) to the reference genes (R) by quantitative PCR (qPCR). The average T/R ratio of multiple single cells corresponded closely to that of a given cell population measured by regular qPCR, and correlated with those of telomere restriction fragments (TRF) and quantitative FISH measurements. Furthermore, SCT-pqPCR detected the telomere length for quiescent cells that are inaccessible by quantitative FISH. The reliability of SCT-pqPCR also was confirmed using sister cells from two cell embryos. Telomere length heterogeneity was identified by SCT-pqPCR among cells of various human and mouse cell types. We found that the T/R values of human fibroblasts at later passages and from old donors were lower and more heterogeneous than those of early passages and from young donors, that cancer cell lines show heterogeneous telomere lengths, that human oocytes and polar bodies have nearly identical telomere lengths, and that the telomere lengths progressively increase from the zygote, two-cell to four-cell embryo. This method will facilitate understanding of telomere heterogeneity and its role in tumorigenesis, aging, and associated diseases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1073/pnas.1306639110DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3666709PMC
May 2013