John E Schjenken

Dr. John E Schjenken

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Research Focus & Metrics

Academic Career Length

20Years (2007-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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27 January 2014 in Proceedings of the National Academy of Sciences
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Journal Article
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JBJohn J. Bromfield
John J. Bromfield
JSJohn E Schjenken
John E Schjenken
PCPeck Y. Chin
Peck Y. Chin
ACAlison S. Care
Alison S. Care
MJMelinda J. Jasper
Melinda J. Jasper
SRSarah A. Robertson
Sarah A. Robertson
Paternal characteristics and exposures influence physiology and disease risks in progeny, but the mechanisms are mostly unknown. Seminal fluid, which affects female reproductive tract gene expression as well as sperm survival and integrity, provides one potential pathway. We evaluated in mice the consequences for offspring of ablating the plasma fraction of seminal fluid by surgical excision of the seminal vesicle gland. Conception was substantially impaired and, when pregnancy did occur, placental hypertrophy was evident in late gestation. After birth, the growth trajectory and metabolic parameters of progeny were altered, most profoundly in males, which exhibited obesity, distorted metabolic hormones, reduced glucose tolerance, and hypertension. Altered offspring phenotype was partly attributable to sperm damage and partly to an effect of seminal fluid deficiency on the female tract, because increased adiposity was also evident in adult male progeny when normal two-cell embryos were transferred to females mated with seminal vesicle-excised males. Moreover, embryos developed in female tracts not exposed to seminal plasma were abnormal from the early cleavage stages, but culture in vitro partly alleviated this. Absence of seminal plasma was accompanied by down-regulation of the embryotrophic factors Lif, Csf2, Il6, and Egf and up-regulation of the apoptosis-inducing factor Trail in the oviduct. These findings show that paternal seminal fluid composition affects the growth and health of male offspring, and reveal that its impact on the periconception environment involves not only sperm protection but also indirect effects on preimplantation embryos via oviduct expression of embryotrophic cytokines. Significance Events at conception shape the future growth and health of offspring, to impact life course potential and disease susceptibility. The environment and experiences of both parents contribute to programming offspring phenotype through epigenetic modifications imparted before embryo implantation. How the father transmits this information remains elusive. Possible pathways include the sperm genome and epigenome, postejaculatory effects of seminal fluid on sperm, and indirect actions of seminal fluid on various female factors regulating embryo development. In this study, we provide evidence that seminal fluid acts to influence both sperm integrity and the balance of embryotrophic and embryotoxic signals in the female reproductive tract, in turn affecting embryo development and programming of future adiposity and metabolic phenotype in male offspring.

1 March 2013 in Science
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KFKa Yee Fung
Ka Yee Fung
NMNiamh E. Mangan
Niamh E. Mangan
HCHelen Cumming
Helen Cumming
JHJay C. Horvat
Jay C. Horvat
JMJemma R. Mayall
Jemma R. Mayall
PHPaul J. Hertzog
Paul J. Hertzog
A Role for IFN-ɛ: Type I interferons (IFNs) are critical cytokines involved in host defense against pathogens, particularly viruses. IFN-ɛ is an IFN-like gene encoded within the type I IFN locus in mice and humans whose function has not been characterized. Fung et al. (p. 1088 ) created mice with a genetic deletion in Ifn -ɛ and found that, like other type I IFNs, IFN-ɛ signals through the IFN-α receptors 1 and 2. However, unlike these other cytokines, which are primarily expressed by immune cells and are induced upon immune cell triggering, IFN-ɛ was expressed exclusively by epithelial cells of the female reproductive tract in both mice and humans and its expression was hormonally regulated. IFN-ɛ–deficient mice were more susceptible to infection with herpes simplex virus 2 and Chlamydia muridarum , two common sexually transmitted pathogens.

1 July 2020 in Physiological Reviews
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JSJohn E Schjenken
John E Schjenken
SRSarah Anne Robertson
Sarah Anne Robertson
Seminal fluid is often assumed to have just one function in mammalian reproduction, delivering sperm to fertilize oocytes. But seminal fluid also transmits signaling agents that interact with female reproductive tissues to facilitate conception and .pregnancy. Upon seminal fluid contact, female tissues initiate a controlled inflammatory response that affects several aspects of reproductive function to ultimately maximize the chances of a male producing healthy offspring. This effect is best characterized in mice, where the female response involves several steps. Initially, seminal fluid factors cause leukocytes to infiltrate the female reproductive tract, and to selectively target and eliminate excess sperm. Other signals stimulate ovulation, induce an altered transcriptional program in female tract tissues that modulates embryo developmental programming, and initiate immune adaptations to promote receptivity to implantation and placental development. A key result is expansion of the pool of regulatory T cells that assist implantation by suppressing inflammation, mediating tolerance to male transplantation antigens, and promoting uterine vascular adaptation and placental development. Principal signaling agents in seminal fluid include prostaglandins and transforming growth factor-β. The balance of male signals affects the nature of the female response, providing a mechanism of ‟cryptic female choiceˮ that influences female reproductive investment. Male-female seminal fluid signaling is evident in all mammalian species investigated including human, and effects of seminal fluid in invertebrates indicate evolutionarily conserved mechanisms. Understanding the female response to seminal fluid will shed new light on infertility and pregnancy disorders and is critical to defining how events at conception influence offspring health.

25 April 2018 in Human Reproduction Update
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Journal Article
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KPKavita Panir
Kavita Panir
JSJohn E Schjenken
John E Schjenken
SRSarah A Robertson
Sarah A Robertson
MHM Louise Hull
M Louise Hull
Endometriosis is a benign gynaecological disorder, which affects 10% of reproductive-aged women and is characterized by endometrial cells from the lining of the uterus being found outside the uterine cavity. However, the pathophysiological mechanisms causing the development of this heterogeneous disease remain enigmatic, and a lack of effective biomarkers necessitates surgical intervention for diagnosis. There is international recognition that accurate non-invasive diagnostic tests and more effective therapies are urgently needed. Non-coding RNA (ncRNA) molecules, which are important regulators of cellular function, have been implicated in many chronic conditions. In endometriosis, transcriptome profiling of tissue samples and functional in vivo and in vitro studies demonstrate that ncRNAs are key contributors to the disease process. In this review, we outline the biogenesis of various ncRNAs relevant to endometriosis and then summarize the evidence indicating their roles in regulatory pathways that govern disease establishment and progression. Articles from 2000 to 2016 were selected for relevance, validity and quality, from results obtained in PubMed, MEDLINE and Google Scholar using the following search terms: ncRNA and reproduction; ncRNA and endometriosis; miRNA and endometriosis; lncRNA and endometriosis; siRNA and endometriosis; endometriosis; endometrial; cervical; ovary; uterus; reproductive tract. All articles were independently screened for eligibility by the authors. This review integrates extensive information from all relevant published studies focusing on microRNAs, long ncRNAs and short inhibitory RNAs in endometriosis. We outline the biological function and synthesis of microRNAs, long ncRNAs and short inhibitory RNAs and provide detailed findings from human research as well as functional studies carried out both in vitro and in vivo, including animal models. Although variability in findings between individual studies exists, collectively, the extant literature justifies the conclusion that dysregulated ncRNAs are a significant element of the endometriosis condition. There is a compelling case that microRNAs, long non-coding RNAs and short inhibitory RNAs have the potential to influence endometriosis development and persistence through modulating inflammation, proliferation, angiogenesis and tissue remodelling. Rapid advances in ncRNA biomarker discovery and therapeutics relevant to endometriosis are emerging. Unravelling the significance of ncRNAs in endometriosis will pave the way for new diagnostic tests and identify new therapeutic targets and treatment approaches that have the potential to improve clinical options for women with this disabling condition.

1 November 2012 in Placenta
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Journal Article
Closed access
JTJ.M. Tolosa
J.M. Tolosa
JSJohn E Schjenken
John E Schjenken
VCVicki Clifton
Vicki Clifton
AVA. Vargas
A. Vargas
BBB. Barbeau
B. Barbeau
RSR. Smith
R. Smith

15 September 2014 in Reproduction in Domestic Animals
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Journal Article
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JSJohn E Schjenken
John E Schjenken
SRSa Robertson
Sa Robertson