Sperm epigenome as a marker of environmental exposure and lifestyle, at the origin of diseases inheritance

Accepted Manuscript Title: SPERM EPIGENOME AS A MARKER OF ENVIRONMENTAL EXPOSURE AND LIFESTYLE, AT THE ORIGIN OF DISEASES INHERITANCE Authors: Benazir Siddeek, Claire Mauduit, Umberto Simeoni, Mohamed Benahmed PII: DOI: Reference:

S1383-5742(17)30122-9 https://doi.org/10.1016/j.mrrev.2018.09.001 MUTREV 8251

To appear in:

Mutation Research

Received date: Revised date: Accepted date:

28-8-2018 4-9-2018 5-9-2018

Please cite this article as: Siddeek B, Mauduit C, Simeoni U, Benahmed M, SPERM EPIGENOME AS A MARKER OF ENVIRONMENTAL EXPOSURE AND LIFESTYLE, AT THE ORIGIN OF DISEASES INHERITANCE, Mutation ResearchReviews in Mutation Research (2018), https://doi.org/10.1016/j.mrrev.2018.09.001 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

SPERM EPIGENOME AS A MARKER OF ENVIRONMENTAL EXPOSURE AND LIFESTYLE, AT THE ORIGIN OF DISEASES INHERITANCE BENAZIR SIDDEEK1, CLAIRE MAUDUIT2, UMBERTO SIMEONI1, MOHAMED BENAHMED2

SC RI PT

1: Woman-Mother-Child-Department, Division of Pediatrics, DOHaD Laboratory, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Rue du Bugnon 46, 1011, Lausanne, Switzerland

2: Inserm, U1065, Centre Méditerranéen de Médecine Moléculaire (C3M), Team 5, Nice, F-06204, France. Correspondence address: Benazir Siddeek, Woman-Mother-Child-Department, Division of Pediatrics,

U

DOHaD Laboratory, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Rue du Bugnon

N

27, 1011, Lausanne, Switzerland Tel: (41) 21 314 32 12; Fax: (41) 21 314 35 72; e-mail:

A

[email protected]

M

Running title: Sperm epigenome and environment

A

CC

EP

TE

D

Graphical Abstract

1

ABSTRACT Paternal exposure to environmental challenges plays a critical role in the offspring's future health and the transmission of acquired traits through generations. This review summarizes our current knowledge in the new field of epigenomic paternal transmission of health and disease. Epidemiological studies identified that

SC RI PT

paternal ageing or challenges (imbalanced diets, stress, toxicants, cigarette smoke, alcohol) increased the risk of offspring to develop diseases such as cancer, metabolic, cardiovascular, and neurological diseases. These data were confirmed and deepened in animal models of exposure to challenges including low-protein, low-folate, high-fat diets, exposure to chemicals such as pesticides and herbicides. Even though some toxicants have mutagenic effect on sperm DNA, changes in sperm epigenome seem to be a common thread

U

between different types of challenges. Indeed, epigenetic changes (DNA methylation, chromatin

N

remodeling, small non-coding RNA) in sperm are described as new mechanisms of intergenerational

A

transmission as demonstrated for dioxin, for example. Those epimutations induce dysregulation in genes

M

expression involved in key cellular pathways such as reactive oxygen species and genome stability regulation, in brain-derived neurotrophic factor, calcium and glucocorticoid signaling, and in lipid and

D

glucose metabolism, leading to diseases in offspring. Finally, since each type of environmental challenges

TE

has its own signature by inducing epimutations at specific genomic loci, the sperm epigenome might be

EP

used as a biomarker in toxicological and risk assessments.

A

CC

Keywords: Epigenome; environment; sperm; intergenerational

2

1 - INTRODUCTION Although the genetic material of an individual contributes to heritability and disease risk, environmental factors, such as diet, lifestyle, exposure to toxicants, adverse and traumatic experiences are also critical to

SC RI PT

health status. The “developmental origins of health and disease” (DOHaD) hypothesis explains how early developmental exposures influence disease onset later in life (for a review, see [1]). This concept [2] now encompasses the effects of numerous exposures on cancer initiation, developmental disorders, neurological diseases, and metabolic syndrome [1, 3]. Indeed, the fetal and early postnatal life is a particularly plastic period since cell differentiation and tissue formation occur at that time. Developmental plasticity allows a

U

predictive adaptive response by the organism to early environmental factors driven by epigenetic mechanisms that control changes in gene expression without modification in DNA sequence [4]. These

N

pathways include DNA methylation (via DNA-methyltransferases, DNMTs), histone modifications

A

(acetylation, methylation, phosphorylation …) that are tightly interrelated with the action of non-coding

M

RNAs. Epigenetic mechanisms are highly dependent on development, both in terms of regulation and

D

stability. Epigenetic programming is vulnerable to deregulation at the time of primary imprint mark erasure

TE

and establishment during gametogenesis [5]. Evidence indicates that parental or ancestral experience may not only affect the parental phenotype but also lead to developmental modifications across generations.

EP

Maternal contribution to intergenerational and transgenerational inheritance has been well documented [6]. Mothers can transmit biomolecules (nutrients or hormones), environmental influences (temperature), and

CC

behavior (anxiety) to their offspring [7-9]. Paternal contribution has been for a long time not considered. Mature sperm was considered as responsible only for the safe transmission of the paternal DNA. Evidence

A

in contrast with this dogma is increasing. Indeed, nowadays, the sperm epigenome is being described as a target for environmental challenges [10] and as a key player in embryonic development [11] and offspring health over the life course [12]. 2 - EPIDEMIOLOGICAL EVIDENCE OF PATERNAL TRANSMISSION

3

Multigenerational effect of paternal role has been suggested by epidemiological observations especially in the context of historical dietary distress. Dutch famine and changes in food supply in North Sweden highlighted a sex-specific increased incidence of obesity [13, 14] in offspring and altered incidence of cardiovascular diseases and diabetes over three generations [15]. Unhealthy dietary behavior in young men

SC RI PT

such as betel nut chewing increases the risk of metabolic syndrome in offspring, in a dose-dependent manner [16]. In the context of exposure to toxicants, the Avon Longitudinal Study described highest mean body mass indexes in the offspring whose fathers started smoking before 11 years [17]. Aside metabolic disturbances, other disorders, such as mental disorders, have been reported to be under paternal influences. As observed during wars, the experience of traumatic stress by fathers is correlated to children's depressive

U

symptoms and anxiety [18]. In physiological conditions as well, the susceptibility in offspring to develop

N

neuropsychiatric disorders (schizophrenia, autism) [19, 20], myotonic dystrophy, Huntington disease and

A

even some forms of cancer [21] is influenced by paternal factors such as ageing. Even if epidemiological

M

studies highlighted human paternal transmission of diseases that are non-Mendelian, they involve several confounding variables that have been clarified by animal models. The development of such models

D

described the molecular bases of the transmission to offspring.

TE

3 – ANIMAL MODELS LINKING PATERNAL EXPOSURE TO ENVIRONMENTAL

EP

CHALLENGES AND OFFSPRING PHENOTYPE Paternal contribution to disease inheritance at the inter- (F1) and transgenerational (F2, F3, F4) levels was

CC

delineated mainly in rodents where male exposed to environmental challenges were crossed with naive females. Those studies revealed that paternal transmission of diseases involves a wide type of challenges

A

(table 1), and affects various physiological functions in the offspring. Majority of studies were interested in paternal nutritional challenges, such as low protein diet [14], low folate, prediabetes, high-fat diet [22], fasting [23], betel nut chewing [24]. Their effects on offspring were metabolic disruption [25], obesity, altered insulin sensitivity and cardiovascular dysfunctions [14, 26]. Based on these models, alterations in cellular pathways have been depicted including decrease of genes involved in calcium signaling, 4

metabolism (Adcy, Plcb, Prkcb, Fto) [14], and in lipid and cholesterol biosynthesis [25]. As well as in human, studies on rodents have strikingly shown that offspring behaviour can be programmed by the father as described in exposures to ethanol [27, 28], cocaine [29] and stress which induce alterations in drug resistance, in reactivity to stress, cognitive dysfunctions and depression [30]; [31], [32]; [33]; [34].

SC RI PT

Glucocorticoid-responsive genes, Olfr151 and Bdnf pathway in the offspring brain seem to be involved in these behavioral alterations.

At the environmental level, ionizing radiations that are well recognized as inducers of genome instability at the individual level were reported to hit offspring genome as well by inducing DNA strand breaks in the

U

thymus [35]. Toxicants such as the fungicide vinclozolin [36] or the pesticide methoxychlor [37] were

N

associated to long-term transgenerational defects that are transmitted through four generations (F1 to F4) with altered male fertility, increased frequencies of tumors, prostate disease, kidney diseases and immune

A

abnormalities, changes in behavior, learning capacity, in mate preference, and anxiety behavior. However,

M

studies performed by a different group did not reproduce those effects. For instance, the transgenerational

D

effects of vinclozolin on fertility [38] were not observed in studies performed on a different rat strain. This

TE

suggests that that genetic variation may be also involved in the effect [39].

EP

4– MOLECULAR BASIS OF PATERNAL TRANSMISSION OF AQUIRED TRAITS 4.1 Overview of the sperm epigenome

CC

Sperm cells are highly specialized cells that ensure the transmission of a proper genetic material from father to offspring. However, several studies, to date, suggest that sperm also propagates non-genetic (epigenetic)

A

information. Such epigenetic transmission may occur through the unique epigenome (RNAs, chromatin, DNA methylation) profile of sperm cells (for review see [40]). DNA methylation is a stable epigenetic mark well-known for its critical role in diverse biological processes such as regulation of gene transcription, transposons silencing, maintenance of genomic imprinting and X chromosome inactivation. DNA methylation is established by DNA methyl transferases (DNMT) 3A and 5

3B, through the addition of a methyl group to a cytosine base, and subsequently preserved throughout cell divisions by the enzyme DNMT1. Loss of this maintenance methylation activity results in passive DNA demethylation. Molecular mechanisms underlying removal of DNA methylation have only now begun to be unraveled [41]. Active DNA demethylation have been suggested including “reverse” enzymatic

SC RI PT

reaction driven by DNA methyltransferases in the absence of S-adenosyl-methionine [42], MBD binding proteins [43] and Ten-Eleven-Translocation (TET) family of enzyme [44]. Global demethylation of the genome occurs twice during development, in pre-implantation embryo and in primordial germ cells where they prevent the heritable transmission of abnormal cytosine methylation (epialleles) from parent to child [45, 46]. The demethylation events are followed by de novo methylation, setting up a pattern inherited

U

throughout development and modified only at tissue-specific loci. TET-dependent demethylation decreases

N

at imprinting control regions (ICRs) and meiotic genes. These stage-specific DNA demethylations are

A

critical for progenitor germ cell differentiation and the ability to transmit DNA from parent to offspring

M

[47]. Chromatin remodeling occurring in germ cells ensures the DNA compaction in spermatozoa. During spermiogenesis, strong nuclear protein remodeling occurs with extreme nuclear condensation leading to

D

highly condensed sperm chromatin. This process is based on the existence of a large number of testis-

TE

specific variants of histone and the histone-to-protamine transition. The disruption of transition proteins induce insufficient sperm nucleus condensation and increase the sensitivity to DNA damage, which can

EP

affect embryogenesis [48]. However, post-translational histones’ modifications can induce the retention of

CC

these histones [49] at promoters of genomic loci. Those histones are preferentially associated with genes involved in development and cell signaling [50, 51], which contribute to transcriptional regulation in the early embryo [49]. The histone H3 lysine 4 (H3K4me3) and lysine 27 trimethylation (H3K27me3) are well

A

studied histone marks. Aberrant epigenetic marks have been associated with abnormal sperm parameters [52] [53], particularly sperm number, motility and morphology [54] [55] and have been proposed as a possible mechanism compromising male fertility. These marks regulate spermatogenesis and play an important role during offspring development [56]. While sperm cells are transcriptionally inactive, microarray analysis identified about 3,000 different transcripts in human spermatozoa [57]. The majority 6

are fragments of longer transcripts, such as ribosomal RNAs, and spermatogenesis-specific RNAs [58]. In addition, spermatozoa contain long and small non-coding RNAs including microRNA (miRNAs) and Piwiinteracting RNA (piRNA). Non-coding RNAs are essential for male germ cells development, maintenance

SC RI PT

and functions and participate in the intergenerational inheritance. A close timely expression of specific testicular miRNAs or enrichment was described which suggests a cell specific expression and function [59-61]. In contrast to miRNAs that are widely expressed in different tissues, piRNAs are predominantly expressed in the germ line [62, 63] where they maintain the integrity of the sperm genome [64, 65]. Indeed, piRNAs are devoted to transposons silencing during primordial germ

U

cell development and throughout adult spermatogenesis in mice (reviewed in [66]). Short endogenous interfering RNA (endo-siRNAs) regulate gene expression post-transcriptionally as well and are also

N

important for transposable elements regulation and thus for genome stability. The relative contribution of

A

endo-siRNAs in germ cell proliferation and in spermatogenesis is still unknown. Two specific small non-

M

coding RNAs were found enriched in mature sperm, designated sperm RNAs (spR) −12 and −13, and their

D

precise functions have yet to be determined. The relative longevity of the spRNAs and their presence into

TE

the nucleus may indicate that they play a role in setting gene expression patterns in the new embryo [67]. RNAs (e.g. tRNAs) can also be the target of modifications that have been associated with diseases in the

EP

offspring [68]. Together, the function of small RNAs ensures proper development and continuation of the germ line through the generations [69].

CC

4.2 Sperm genome is sensitive to environmental challenges

A

A number of reports support the mutagenic effect of environment on sperm DNA. In contrast to radiations [70], drugs used in chemotherapy [71], tobacco smoke [72], and pollutants [73] that have been described as germ line mutagens, less number of studies addressed the dietary effects on germ cell mutation rates. The rare studies performed on Western-style diet highlighted increased frequencies of sperm disomy [74], increased DNA damage associated with increased oxidative stress [75]. Interestingly, sperm DNA

7

alterations induced by obesity can be reduced by dietary approach and exercise [76]. Furthermore, observations associating paternal exposure to irradiation, hydrocarbons such as diesel fuel, industrial solvent, mineral oils, cigarette smoke, pesticides, paint, wood dust, lacquer thinner, turpentine, dyes, or pigments with increased incidence of Wilms’ tumor [77], leukemia [78, 79], neuroblastoma [80], lymphoma

SC RI PT

[81] and brain cancer [82, 83] in offspring raised the question of a possible paternal role in intergenerational carcinogesis. However, this hypothesis of intergenerational carcinogenesis has long been controversial. Indeed, contradictory observations have been reported [84]. Also, genome-wide association studies (GWAS) of common genetic variants have only accounted for a small proportion of the estimated heritability of cancers. In this context, epimutations have been proposed as another potential mechanism

U

to explain some of the 'missing' causality and heritability of cancer and an alternative to Mendelian

N

inheritance. Indeed, alterations in epigenetic mechanisms regulating pathways involved in genome stability

A

represent key factors underlying the molecular aetiology of transgenerational effects [35] [85]. DNA

M

methylation have been widely described as a master mechanism regulating the expression of genes involved in tumor suppression [86] and DNA repair [87]. Through the control of germline-specific piRNAs,

D

DNA methylation is a safeguard mechanisms in genome stability by controlling transposable elements.

TE

This interrelation between genome stability and epigenetic is pictured with ROS signalling. Dysregulation of the homeostasis between reactive oxygen species (ROS) and cell antioxidant and repair mechanisms can

EP

lead to oxidative stress. ROS have been described as regulators of DNA methyl transferases and histone

CC

modifiers [88]. In this sense, sperm exposure to ROS has been associated with global alteration in DNA methylation [89] which could represent a potential underlying mechanism of the following embryonic development defects and altered metabolism in the female offspring [90]. Certain type of compounds have

A

the capacity to directly alkylate DNA. This is the case of Methyl Parathion (Me-Pa) which is an oxidizing organophosphate pesticide that decreases the global DNA methylation pattern and increases the methylation of two CpG sites within 8-oxoguanine DNA glycosidase (Ogg1) promoter and one CpG site within nuclear factor erythroid 2-like 2 (Nfe2l2) promoter. Thus DNA methylation seems to be a pathway involved in the genetic and oxidative damage in sperm cells induced by exposure to Me-Pa [91]. Similarly, mice exposed 8

to particulate air pollution show sperm DNA hypermethylation and increased germ-line DNA mutation frequencies [64]. 4.3 Sperm epigenome is sensitive to environmental challenges

SC RI PT

The epigenetic mechanisms that draw the sperm epigenome are sensitive to environment and life style. At the cell level, exposure of sperm cells to environmental challenges is associated with different epigenetic profile. For instance, heat (65°C) was reported to alter H3K27me3 mark which lowers notably embryo implantation rate [11]. Even though not yet explored, we can speculate that this alteration in H3K27 trimethylation driven by heat is attributed to modifications in polycomb proteins. Indeed, the activity and

U

the expression of these enzymes have been reported to be regulated by temperature [91].

At the organism level, majority of studies analyzed sperm DNA methylation and associated alteration in its

N

profile with deleterious gene expression in the offspring. Thereby, in ageing, DNA methylation regions

A

(DMR) were associated with age and corresponded to genes involved in schizophrenia and bipolar disorder

M

[92, 93]. Alterations in DNA methylation have also been reported in the sperm of mice exposed to X-ray

D

(controlling H19 gene) [10], chemotherapy [94], to odor fear conditioning (regulating Olfr151) [34].

TE

Interestingly, in the inter- and trans- generational effects in response to paternal exposure to endocrine disruptors, alterations in DNA methylation profile seem to be a common thread. In fact, differential DMR

EP

are induced by the insecticide Dichlorodiphenyltrichloroethane (DDT) [95], the plastic derived compounds bisphenol-A (BPA), bis(2-ethylhexyl)phthalate (DEHP) and dibutyl phthalate (DBP) [96], the hydrocarbon

CC

mixture involving jet fuel (JP-8), and the dioxin 2,3,7,8-tetrachlorodibenzo[p]dioxin (TCDD) [97]. One possible explanation for DMR may involve altered expression of DNMTs in testicular germ cells [98]. In

A

offspring specific tissues, altered gene expression levels were associated with differential DMR in the father’s sperm cells. As such, altered expression in Proopiomelacortin and Bdnf in the ventral tegmental area were associated with paternal exposure to ethanol [99] [100]. Thus, sperm DMR appear as potential biomarkers for intergenerational disease and/or ancestral environmental challenges. In a lesser extent than methylome, sperm chromatin was reported to be sensitive to environmental challenges especially to

9

toxicants. In the cases of exposure to cocaine and to cigarette smoke, increased acetylation of histone H3 in Bdnf promoters [29] and abnormalities in histone-to-protamine transition [101] [102] have been linked to offspring behavioral defects. Exposure to endocrine disruptors were associated with long-term decreased trimethylation levels of the histone H3K27, due to altered testicular expression of enhancer of zeste

SC RI PT

homologue 2 (EZH2) [103]. In dietary distress such as exposure to low- folate diet, reduced H3K4, K9 monomethylation and reduced H3K9 trimethylation were reported in spermatozoa [26]. Recently, increasing evidence based on wide approaches such as deep sequencing have pointed out the critical role of non-coding RNAs in the paternal transmission of diseases. Sperm miRNAs profile is influenced by a wide range of environmental challenges such as irradiation (miR-29) [104], exposure to endocrine

U

disruptors (miR-29, miR-101) [98, 103], prediabetes [105], obesity [22], stress (including miR-375-3p,

N

miR-375-5p) [31], exercise (miR -503, miR-542-3p and mir-465b-5p) [106]. As well as miRNAs, other

A

classes of small non-coding RNAs present deep alterations following an environmental challenge. For

M

instance, alteration in tRNA-derived small RNAs (tsRNAs) profile in the sperm of animals exposed to highfat diet [12], and down-regulation of a piRNAs cluster in the sperm of stressed animals [31] have been

D

reported. Interestingly, piRNAs have been described as stable key players in multigenerational epigenetic

5

-

EVIDENCE

TE

memory in the germline of c. elegans (lasting at least 20 generations) [107]. FOR

THE

INTERGENERATIONAL

AND

TRANSGENERATIONAL

EP

TRANSMISSION THROUGH SPERM SMALL NON-CODING RNAS

CC

The evidence in mammals that sperm RNAs can act as transgenerational carriers of acquired trait has been provided recently through the collection of RNAs from the F1 males’ sperm and their injection into

A

fertilized eggs from normal mice. Dicer and Drosha represent critical enzymes for miRNAs biogenesis. Realizing sperm injection (ICSI) from Dicer and Drosha knock out mice, Shuiqiao Yuan et al described a crucial function of paternal miRNAs and/or endosiRNAs in the control of the transcriptomic homeostasis in fertilized eggs, zygotes and two-cell embryos, which could be rescued by injecting wild type sperm-derived total or small RNAs into ICSI 10

embryos [108]. In longer term, altered sperm miRNAs profile can induce disease development in offspring. This sperm miRNAs based disease programming was observed in animal exposed to stress and to high-fat diet. Mansuy and colleagues showed that injecting sperm RNAs into zygotes recapitulates the transgenerational effects of trauma. In their study, they identified specific miRNAs among other non-coding

SC RI PT

RNAs that transmit stress to offspring. Further, they demonstrated that injected miRNAs knock down expression of specific genes in zygotes [31]. In the context of paternal exposure to dietary distress, the injection of sperm RNAs (predominantly tsRNAs) into normal zygotes resulted in altered expression of genes involved in metabolic pathways; this RNA fraction also affected the metabolic phenotype in offspring [12, 68]. Rando and colleagues provided evidence that tsRNAs are delivered to sperm via vesicles that fuse

U

with sperm in the epididymis [68]. They found an increase in N2-methylguanosines and 5-methylcytidines

N

in the tsRNAs of protein restricted diet sperm, a modification that seems to be essential for the transmission

A

of the metabolic alterations. Those experiments demonstrate that sperm epigenome alterations driven by

M

environmental challenges not only occur in the testis but also during sperm cells maturation in epididymis. Injection of sperm born non-coding RNAs can drive pathogenesis in offspring, however, there are still

D

remaining questions. Indeed, unlike DNA methylation or chromatin modifications, miRNA levels in

TE

mammals do not persist from cell division to cell division, thus, the link between offspring tissular

EP

alterations and sperm miRNAs levels need to be clarified. 6 - CONCLUSION AND PERSPECTIVE

CC

The recent advances in epigenetic research highlight the sperm epigenome as a sensitive target for a wide range of environmental challenges and demonstrate the role of its alterations in offspring disease

A

programming. Among epigenetic regulations, non-coding RNAs including miRNAs present particular interests. Notably, miRNAs seem to be key players in the inter- and transgenerational transmission of acquired traits. Due to their high stability in body fluids and easiness to measure, miRNAs have been presented as sensitive biomarkers [103, 109] to be used in innovative and non-invasive tests in diagnosis, in prognosis, in the evaluation of treatment efficiency [110, 111], and as potential biomarkers in toxicology 11

[112]. Thus, in toxicological assessments, sperm epigenome seem to be an important target to analyse and appropriate guidelines should be developed. Furthermore, the specificity of the sperm epigenetic mark induced by each challenge, the windows of exposure and the effects of combined exposure on sperm

SC RI PT

epigenome are critical points to address. FUNDINGS

This work was supported by the Centre Hospitalier Universitaire Vaudoix. REFERENCES

A

CC

EP

TE

D

M

A

N

U

[1] A.J. Bernal, R.L. Jirtle, Epigenomic disruption: the effects of early developmental exposures, Birth Defects Res A Clin Mol Teratol, 88 (2010) 938-944. [2] D.J. Barker, P.D. Winter, C. Osmond, B. Margetts, S.J. Simmonds, Weight in infancy and death from ischaemic heart disease, Lancet, 2 (1989) 577-580. [3] D.J. Barker, In utero programming of cardiovascular disease, Theriogenology, 53 (2000) 555-574. [4] R. Barouki, P.D. Gluckman, P. Grandjean, M. Hanson, J.J. Heindel, Developmental origins of noncommunicable disease: implications for research and public health, Environmental health : a global access science source, 11 (2012) 42. [5] R.L. Jirtle, M.K. Skinner, Environmental epigenomics and disease susceptibility, Nat Rev Genet, 8 (2007) 253-262. [6] E.B. Keverne, Genomic imprinting, action, and interaction of maternal and fetal genomes, Proceedings of the National Academy of Sciences of the United States of America, (2014). [7] R. Gitau, A. Cameron, N.M. Fisk, V. Glover, Fetal exposure to maternal cortisol, Lancet, 352 (1998) 707708. [8] H. Rashid, M. Kagami, F. Ferdous, E. Ma, T. Terao, T. Hayashi, Y. Wagatsuma, Temperature during pregnancy influences the fetal growth and birth size, Trop Med Health, 45 (2017) 1. [9] X. Zhang, X. Wu, B. Lei, Y. Jing, Z. Jiang, X. Zhang, X. Fang, Y. Yu, Transplacental transfer characteristics of organochlorine pesticides in paired maternal and cord sera, and placentas and possible influencing factors, Environ Pollut, 233 (2017) 446-454. [10] B. Zhu, X. Huang, J. Chen, Y. Lu, Y. Chen, J. Zhao, Methylation changes of H19 gene in sperms of Xirradiated mouse and maintenance in offspring, Biochem Biophys Res Commun, 340 (2006) 83-89. [11] S.B. Chao, L. Chen, J.C. Li, X.H. Ou, X.J. Huang, S. Wen, Q.Y. Sun, G.L. Gao, Defective histone H3K27 trimethylation modification in embryos derived from heated mouse sperm, Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada, 18 (2012) 476-482. [12] Q. Chen, M. Yan, Z. Cao, X. Li, Y. Zhang, J. Shi, G.H. Feng, H. Peng, X. Zhang, Y. Zhang, J. Qian, E. Duan, Q. Zhai, Q. Zhou, Sperm tsRNAs contribute to intergenerational inheritance of an acquired metabolic disorder, Science, 351 (2016) 397-400. [13] M.V. Veenendaal, R.C. Painter, S.R. de Rooij, P.M. Bossuyt, J.A. van der Post, P.D. Gluckman, M.A. Hanson, T.J. Roseboom, Transgenerational effects of prenatal exposure to the 1944-45 Dutch famine, BJOG : an international journal of obstetrics and gynaecology, 120 (2013) 548-553.

12

A

CC

EP

TE

D

M

A

N

U

SC RI PT

[14] A.J. Watkins, K.D. Sinclair, Paternal low protein diet affects adult offspring cardiovascular and metabolic function in mice, Am J Physiol Heart Circ Physiol, 306 (2014) H1444-1452. [15] L.O. Bygren, P. Tinghog, J. Carstensen, S. Edvinsson, G. Kaati, M.E. Pembrey, M. Sjostrom, Change in paternal grandmothers' early food supply influenced cardiovascular mortality of the female grandchildren, BMC genetics, 15 (2014) 12. [16] T.H. Chen, Y.H. Chiu, B.J. Boucher, Transgenerational effects of betel-quid chewing on the development of the metabolic syndrome in the Keelung Community-based Integrated Screening Program, Am J Clin Nutr, 83 (2006) 688-692. [17] K. Northstone, J. Golding, G. Davey Smith, L.L. Miller, M. Pembrey, Prepubertal start of father's smoking and increased body fat in his sons: further characterisation of paternal transgenerational responses, European journal of human genetics : EJHG, 22 (2014) 1382-1386. [18] M. Schick, N. Morina, R. Klaghofer, U. Schnyder, J. Muller, Trauma, mental health, and intergenerational associations in Kosovar Families 11 years after the war, European journal of psychotraumatology, 4 (2013). [19] A. Sipos, F. Rasmussen, G. Harrison, P. Tynelius, G. Lewis, D.A. Leon, D. Gunnell, Paternal age and schizophrenia: a population based cohort study, BMJ, 329 (2004) 1070. [20] A. Reichenberg, R. Gross, M. Weiser, M. Bresnahan, J. Silverman, S. Harlap, J. Rabinowitz, C. Shulman, D. Malaspina, G. Lubin, H.Y. Knobler, M. Davidson, E. Susser, Advancing paternal age and autism, Arch Gen Psychiatry, 63 (2006) 1026-1032. [21] Y. Lu, H. Ma, J. Sullivan-Halley, K.D. Henderson, E.T. Chang, C.A. Clarke, S.L. Neuhausen, D.W. West, L. Bernstein, S.S. Wang, Parents' ages at birth and risk of adult-onset hematologic malignancies among female teachers in California, Am J Epidemiol, 171 (2010) 1262-1269. [22] T. Fullston, E.M. Ohlsson Teague, N.O. Palmer, M.J. DeBlasio, M. Mitchell, M. Corbett, C.G. Print, J.A. Owens, M. Lane, Paternal obesity initiates metabolic disturbances in two generations of mice with incomplete penetrance to the F2 generation and alters the transcriptional profile of testis and sperm microRNA content, FASEB journal : official publication of the Federation of American Societies for Experimental Biology, 27 (2013) 4226-4243. [23] L.M. Anderson, L. Riffle, R. Wilson, G.S. Travlos, M.S. Lubomirski, W.G. Alvord, Preconceptional fasting of fathers alters serum glucose in offspring of mice, Nutrition, 22 (2006) 327-331. [24] B.J. Boucher, S.W. Ewen, J.M. Stowers, Betel nut (Areca catechu) consumption and the induction of glucose intolerance in adult CD1 mice and in their F1 and F2 offspring, Diabetologia, 37 (1994) 49-55. [25] B.R. Carone, L. Fauquier, N. Habib, J.M. Shea, C.E. Hart, R. Li, C. Bock, C. Li, H. Gu, P.D. Zamore, A. Meissner, Z. Weng, H.A. Hofmann, N. Friedman, O.J. Rando, Paternally induced transgenerational environmental reprogramming of metabolic gene expression in mammals, Cell, 143 (2010) 1084-1096. [26] R. Lambrot, C. Xu, S. Saint-Phar, G. Chountalos, T. Cohen, M. Paquet, M. Suderman, M. Hallett, S. Kimmins, Low paternal dietary folate alters the mouse sperm epigenome and is associated with negative pregnancy outcomes, Nat Commun, 4 (2013) 2889. [27] E.L. Abel, Paternal alcohol exposure and hyperactivity in rat offspring: effects of amphetamine, Neurotoxicology and teratology, 15 (1993) 445-449. [28] P.A. Jamerson, M.J. Wulser, B.F. Kimler, Neurobehavioral effects in rat pups whose sires were exposed to alcohol, Brain research. Developmental brain research, 149 (2004) 103-111. [29] F.M. Vassoler, S.L. White, H.D. Schmidt, G. Sadri-Vakili, R.C. Pierce, Epigenetic inheritance of a cocaine-resistance phenotype, Nature neuroscience, 16 (2013) 42-47. [30] C. Hoyer, H. Richter, C. Brandwein, M.A. Riva, P. Gass, Preconceptional paternal exposure to a single traumatic event affects postnatal growth of female but not male offspring, Neuroreport, 24 (2013) 856860.

13

A

CC

EP

TE

D

M

A

N

U

SC RI PT

[31] K. Gapp, A. Jawaid, P. Sarkies, J. Bohacek, P. Pelczar, J. Prados, L. Farinelli, E. Miska, I.M. Mansuy, Implication of sperm RNAs in transgenerational inheritance of the effects of early trauma in mice, Nature neuroscience, 17 (2014) 667-669. [32] R. Mychasiuk, A. Harker, S. Ilnytskyy, R. Gibb, Paternal stress prior to conception alters DNA methylation and behaviour of developing rat offspring, Neuroscience, 241 (2013) 100-105. [33] A.B. Rodgers, C.P. Morgan, S.L. Bronson, S. Revello, T.L. Bale, Paternal stress exposure alters sperm microRNA content and reprograms offspring HPA stress axis regulation, J Neurosci, 33 (2013) 9003-9012. [34] B.G. Dias, K.J. Ressler, Parental olfactory experience influences behavior and neural structure in subsequent generations, Nature neuroscience, 17 (2014) 89-96. [35] I. Koturbash, M. Baker, J. Loree, K. Kutanzi, D. Hudson, I. Pogribny, O. Sedelnikova, W. Bonner, O. Kovalchuk, Epigenetic dysregulation underlies radiation-induced transgenerational genome instability in vivo, Int J Radiat Oncol Biol Phys, 66 (2006) 327-330. [36] J.R. McCarrey, J.D. Lehle, S.S. Raju, Y. Wang, E.E. Nilsson, M.K. Skinner, Tertiary Epimutations - A Novel Aspect of Epigenetic Transgenerational Inheritance Promoting Genome Instability, PLoS One, 11 (2016) e0168038. [37] A. Paoloni-Giacobino, Epigenetic effects of methoxychlor and vinclozolin on male gametes, Vitam Horm, 94 (2014) 211-227. [38] M.D. Anway, A.S. Cupp, M. Uzumcu, M.K. Skinner, Epigenetic transgenerational actions of endocrine disruptors and male fertility, Science, 308 (2005) 1466-1469. [39] S. Schneider, W. Kaufmann, R. Buesen, B. van Ravenzwaay, Vinclozolin--the lack of a transgenerational effect after oral maternal exposure during organogenesis, Reprod Toxicol, 25 (2008) 352-360. [40] E. Casas, T. Vavouri, Sperm epigenomics: challenges and opportunities, Front Genet, 5 (2014) 330. [41] H. Wu, Y. Zhang, Reversing DNA methylation: mechanisms, genomics, and biological functions, Cell, 156 (2014) 45-68. [42] S. Kangaspeska, B. Stride, R. Metivier, M. Polycarpou-Schwarz, D. Ibberson, R.P. Carmouche, V. Benes, F. Gannon, G. Reid, Transient cyclical methylation of promoter DNA, Nature, 452 (2008) 112-115. [43] S.K. Bhattacharya, S. Ramchandani, N. Cervoni, M. Szyf, A mammalian protein with specific demethylase activity for mCpG DNA, Nature, 397 (1999) 579-583. [44] P.W. Hill, R. Amouroux, P. Hajkova, DNA demethylation, Tet proteins and 5-hydroxymethylcytosine in epigenetic reprogramming: an emerging complex story, Genomics, 104 (2014) 324-333. [45] E. Heard, R.A. Martienssen, Transgenerational epigenetic inheritance: myths and mechanisms, Cell, 157 (2014) 95-109. [46] S. Gkountela, K.X. Zhang, T.A. Shafiq, W.W. Liao, J. Hargan-Calvopina, P.Y. Chen, A.T. Clark, DNA Demethylation Dynamics in the Human Prenatal Germline, Cell, 161 (2015) 1425-1436. [47] J. Hargan-Calvopina, S. Taylor, H. Cook, Z. Hu, S.A. Lee, M.R. Yen, Y.S. Chiang, P.Y. Chen, A.T. Clark, Stage-Specific Demethylation in Primordial Germ Cells Safeguards against Precocious Differentiation, Dev Cell, 39 (2016) 75-86. [48] V.W. Aoki, S.I. Moskovtsev, J. Willis, L. Liu, J.B. Mullen, D.T. Carrell, DNA integrity is compromised in protamine-deficient human sperm, Journal of andrology, 26 (2005) 741-748. [49] M. Ihara, M.L. Meyer-Ficca, N.A. Leu, S. Rao, F. Li, B.D. Gregory, I.A. Zalenskaya, R.M. Schultz, R.G. Meyer, Paternal poly (ADP-ribose) metabolism modulates retention of inheritable sperm histones and early embryonic gene expression, PLoS Genet, 10 (2014) e1004317. [50] U. Brykczynska, M. Hisano, S. Erkek, L. Ramos, E.J. Oakeley, T.C. Roloff, C. Beisel, D. Schubeler, M.B. Stadler, A.H. Peters, Repressive and active histone methylation mark distinct promoters in human and mouse spermatozoa, Nat Struct Mol Biol, 17 (2010) 679-687.

14

A

CC

EP

TE

D

M

A

N

U

SC RI PT

[51] A. Arpanahi, M. Brinkworth, D. Iles, S.A. Krawetz, A. Paradowska, A.E. Platts, M. Saida, K. Steger, P. Tedder, D. Miller, Endonuclease-sensitive regions of human spermatozoal chromatin are highly enriched in promoter and CTCF binding sequences, Genome Res, 19 (2009) 1338-1349. [52] S.K. Kim, B.C. Jee, S.H. Kim, Histone methylation and acetylation in ejaculated human sperm: effects of swim-up and smoking, Fertil Steril, 103 (2015) 1425-1431. [53] K.I. Aston, V. Punj, L. Liu, D.T. Carrell, Genome-wide sperm deoxyribonucleic acid methylation is altered in some men with abnormal chromatin packaging or poor in vitro fertilization embryogenesis, Fertil Steril, 97 (2012) 285-292. [54] T.G. Jenkins, K.I. Aston, T.D. Meyer, J.M. Hotaling, M.B. Shamsi, E.B. Johnstone, K.J. Cox, J.B. Stanford, C.A. Porucznik, D.T. Carrell, Decreased fecundity and sperm DNA methylation patterns, Fertil Steril, 105 (2016) 51-57 e51-53. [55] Y. Du, M. Li, J. Chen, Y. Duan, X. Wang, Y. Qiu, Z. Cai, Y. Gui, H. Jiang, Promoter targeted bisulfite sequencing reveals DNA methylation profiles associated with low sperm motility in asthenozoospermia, Hum Reprod, 31 (2016) 24-33. [56] S.S. Hammoud, D.A. Nix, H. Zhang, J. Purwar, D.T. Carrell, B.R. Cairns, Distinctive chromatin in human sperm packages genes for embryo development, Nature, 460 (2009) 473-478. [57] R.P. Martins, S.A. Krawetz, RNA in human sperm, Asian journal of andrology, 7 (2005) 115-120. [58] M. Soumillon, A. Necsulea, M. Weier, D. Brawand, X. Zhang, H. Gu, P. Barthes, M. Kokkinaki, S. Nef, A. Gnirke, M. Dym, B. de Massy, T.S. Mikkelsen, H. Kaessmann, Cellular source and mechanisms of high transcriptome complexity in the mammalian testis, Cell reports, 3 (2013) 2179-2190. [59] K. Hayashi, S.M. Chuva de Sousa Lopes, M. Kaneda, F. Tang, P. Hajkova, K. Lao, D. O'Carroll, P.P. Das, A. Tarakhovsky, E.A. Miska, M.A. Surani, MicroRNA biogenesis is required for mouse primordial germ cell development and spermatogenesis, PloS one, 3 (2008) e1738. [60] G.M. Buchold, C. Coarfa, J. Kim, A. Milosavljevic, P.H. Gunaratne, M.M. Matzuk, Analysis of microRNA expression in the prepubertal testis, PloS one, 5 (2010) e15317. [61] E. Marcon, T. Babak, G. Chua, T. Hughes, P.B. Moens, miRNA and piRNA localization in the male mammalian meiotic nucleus, Chromosome research : an international journal on the molecular, supramolecular and evolutionary aspects of chromosome biology, 16 (2008) 243-260. [62] M.C. Siomi, K. Sato, D. Pezic, A.A. Aravin, PIWI-interacting small RNAs: the vanguard of genome defence, Nat Rev Mol Cell Biol, 12 (2011) 246-258. [63] O. Meikar, M. Da Ros, H. Liljenback, J. Toppari, N. Kotaja, Accumulation of piRNAs in the chromatoid bodies purified by a novel isolation protocol, Exp Cell Res, 316 (2010) 1567-1575. [64] S.M. Hawkins, G.M. Buchold, M.M. Matzuk, Minireview: The roles of small RNA pathways in reproductive medicine, Molecular endocrinology, 25 (2011) 1257-1279. [65] A. Molaro, E. Hodges, F. Fang, Q. Song, W.R. McCombie, G.J. Hannon, A.D. Smith, Sperm methylation profiles reveal features of epigenetic inheritance and evolution in primates, Cell, 146 (2011) 1029-1041. [66] A.A. Aravin, G.J. Hannon, Small RNA silencing pathways in germ and stem cells, Cold Spring Harbor symposia on quantitative biology, 73 (2008) 283-290. [67] M. Kawano, H. Kawaji, V. Grandjean, J. Kiani, M. Rassoulzadegan, Novel small noncoding RNAs in mouse spermatozoa, zygotes and early embryos, PloS one, 7 (2012) e44542. [68] U. Sharma, C.C. Conine, J.M. Shea, A. Boskovic, A.G. Derr, X.Y. Bing, C. Belleannee, A. Kucukural, R.W. Serra, F. Sun, L. Song, B.R. Carone, E.P. Ricci, X.Z. Li, L. Fauquier, M.J. Moore, R. Sullivan, C.C. Mello, M. Garber, O.J. Rando, Biogenesis and function of tRNA fragments during sperm maturation and fertilization in mammals, Science, 351 (2016) 391-396. [69] T.U. Banisch, M. Goudarzi, E. Raz, Small RNAs in germ cell development, Curr Top Dev Biol, 99 (2012) 79-113.

15

A

CC

EP

TE

D

M

A

N

U

SC RI PT

[70] M. Kodaira, J.I. Asakawa, N. Nakamura, Radiation-Induced Deletions in Mouse Spermatogonia are Usually Large (over 200 kb) and Contain Little Sequence Similarity at the Junctions, Radiat Res, 187 (2017) 722-731. [71] F. Marchetti, J. Bishop, J. Gingerich, A.J. Wyrobek, Meiotic interstrand DNA damage escapes paternal repair and causes chromosomal aberrations in the zygote by maternal misrepair, Sci Rep, 5 (2015) 7689. [72] F. Marchetti, A. Rowan-Carroll, A. Williams, A. Polyzos, M.L. Berndt-Weis, C.L. Yauk, Sidestream tobacco smoke is a male germ cell mutagen, Proceedings of the National Academy of Sciences of the United States of America, 108 (2011) 12811-12814. [73] C. Yauk, A. Polyzos, A. Rowan-Carroll, C.M. Somers, R.W. Godschalk, F.J. Van Schooten, M.L. Berndt, I.P. Pogribny, I. Koturbash, A. Williams, G.R. Douglas, O. Kovalchuk, Germ-line mutations, DNA damage, and global hypermethylation in mice exposed to particulate air pollution in an urban/industrial location, Proceedings of the National Academy of Sciences of the United States of America, 105 (2008) 605-610. [74] J. Jurewicz, M. Radwan, W. Sobala, J. Gromadzinska, E. Jablonska, P. Radwan, L. Jakubowski, W. Wasowicz, W. Hanke, Dietary Patterns and the Frequency of Disomy in Human Sperm, Urology, 93 (2016) 86-91. [75] H.W. Bakos, M. Mitchell, B.P. Setchell, M. Lane, The effect of paternal diet-induced obesity on sperm function and fertilization in a mouse model, Int J Androl, 34 (2011) 402-410. [76] N.O. Palmer, H.W. Bakos, J.A. Owens, B.P. Setchell, M. Lane, Diet and exercise in an obese mouse fed a high-fat diet improve metabolic health and reverse perturbed sperm function, American journal of physiology. Endocrinology and metabolism, 302 (2012) E768-780. [77] J.R. Wilkins, 3rd, T.H. Sinks, Jr., Paternal occupation and Wilms' tumour in offspring, J Epidemiol Community Health, 38 (1984) 7-11. [78] H.D. Bailey, C. Metayer, E. Milne, E.T. Petridou, C. Infante-Rivard, L.G. Spector, J. Clavel, J.D. Dockerty, L. Zhang, B.K. Armstrong, J. Rudant, L. Fritschi, A. Amigou, E. Hatzipantelis, A.Y. Kang, E. Stiakaki, J. Schuz, Home paint exposures and risk of childhood acute lymphoblastic leukemia: findings from the Childhood Leukemia International Consortium, Cancer Causes Control, 26 (2015) 1257-1270. [79] M.A. Castro-Jimenez, L.C. Orozco-Vargas, Parental exposure to carcinogens and risk for childhood acute lymphoblastic leukemia, Colombia, 2000-2005, Prev Chronic Dis, 8 (2011) A106. [80] A.J. De Roos, A.F. Olshan, K. Teschke, C. Poole, D.A. Savitz, J. Blatt, M.L. Bondy, B.H. Pollock, Parental occupational exposures to chemicals and incidence of neuroblastoma in offspring, Am J Epidemiol, 154 (2001) 106-114. [81] R. Zheng, Q. Zhang, Q. Zhang, L. Yang, Z. Zhang, F. Huang, Occupational exposure to pentachlorophenol causing lymphoma and hematopoietic malignancy for two generations, Toxicol Ind Health, 31 (2015) 328-342. [82] S. Peters, D.C. Glass, K.R. Greenop, B.K. Armstrong, M. Kirby, E. Milne, L. Fritschi, Childhood brain tumours: associations with parental occupational exposure to solvents, Br J Cancer, 111 (2014) 998-1003. [83] K.R. Greenop, S. Peters, H.D. Bailey, L. Fritschi, J. Attia, R.J. Scott, D.C. Glass, N.H. de Klerk, F. Alvaro, B.K. Armstrong, E. Milne, Exposure to pesticides and the risk of childhood brain tumors, Cancer Causes Control, 24 (2013) 1269-1278. [84] M.G. Forest, A. Lecoq, M. David, M. Pugeat, Effects of human chorionic gonadotropin, androgens, adrenocorticotropin hormone, dexamethasone and hyperprolactinemia on plasma sex steroid-binding protein, Ann N Y Acad Sci, 538 (1988) 214-234. [85] J.E. Baulch, O.G. Raabe, Gamma irradiation of Type B spermatogonia leads to heritable genomic instability in four generations of mice, Mutagenesis, 20 (2005) 337-343. [86] A. Kazanets, T. Shorstova, K. Hilmi, M. Marques, M. Witcher, Epigenetic silencing of tumor suppressor genes: Paradigms, puzzles, and potential, Biochim Biophys Acta, 1865 (2016) 275-288.

16

A

CC

EP

TE

D

M

A

N

U

SC RI PT

[87] X. Zhu, L. Shan, F. Wang, J. Wang, F. Wang, G. Shen, X. Liu, B. Wang, Y. Yuan, J. Ying, H. Yang, Hypermethylation of BRCA1 gene: implication for prognostic biomarker and therapeutic target in sporadic primary triple-negative breast cancer, Breast Cancer Res Treat, 150 (2015) 479-486. [88] I. Afanas'ev, Mechanisms of superoxide signaling in epigenetic processes: relation to aging and cancer, Aging Dis, 6 (2015) 216-227. [89] O. Tunc, K. Tremellen, Oxidative DNA damage impairs global sperm DNA methylation in infertile men, J Assist Reprod Genet, 26 (2009) 537-544. [90] M. Lane, N.O. McPherson, T. Fullston, M. Spillane, L. Sandeman, W.X. Kang, D.L. Zander-Fox, Oxidative stress in mouse sperm impairs embryo development, fetal growth and alters adiposity and glucose regulation in female offspring, PLoS One, 9 (2014) e100832. [91] F. Marasca, B. Bodega, V. Orlando, How Polycomb-Mediated Cell Memory Deals With a Changing Environment: Variations in PcG complexes and proteins assortment convey plasticity to epigenetic regulation as a response to environment, Bioessays, 40 (2018) e1700137. [92] T.G. Jenkins, K.I. Aston, C. Pflueger, B.R. Cairns, D.T. Carrell, Age-associated sperm DNA methylation alterations: possible implications in offspring disease susceptibility, PLoS genetics, 10 (2014) e1004458. [93] J.R. Kovac, J. Addai, R.P. Smith, R.M. Coward, D.J. Lamb, L.I. Lipshultz, The effects of advanced paternal age on fertility, Asian journal of andrology, 15 (2013) 723-728. [94] M. Shnorhavorian, S.M. Schwartz, B. Stansfeld, I. Sadler-Riggleman, D. Beck, M.K. Skinner, Differential DNA Methylation Regions in Adult Human Sperm following Adolescent Chemotherapy: Potential for Epigenetic Inheritance, PLoS One, 12 (2017) e0170085. [95] M.K. Skinner, M. Manikkam, R. Tracey, C. Guerrero-Bosagna, M. Haque, E.E. Nilsson, Ancestral dichlorodiphenyltrichloroethane (DDT) exposure promotes epigenetic transgenerational inheritance of obesity, BMC Med, 11 (2013) 228. [96] M. Manikkam, R. Tracey, C. Guerrero-Bosagna, M.K. Skinner, Plastics derived endocrine disruptors (BPA, DEHP and DBP) induce epigenetic transgenerational inheritance of obesity, reproductive disease and sperm epimutations, PLoS One, 8 (2013) e55387. [97] R. Tracey, M. Manikkam, C. Guerrero-Bosagna, M.K. Skinner, Hydrocarbons (jet fuel JP-8) induce epigenetic transgenerational inheritance of obesity, reproductive disease and sperm epimutations, Reprod Toxicol, 36 (2013) 104-116. [98] L. Meunier, B. Siddeek, A. Vega, N. Lakhdari, L. Inoubli, R.P. Bellon, G. Lemaire, C. Mauduit, M. Benahmed, Perinatal programming of adult rat germ cell death after exposure to xenoestrogens: role of microRNA miR-29 family in the down-regulation of DNA methyltransferases and Mcl-1, Endocrinology, 153 (2012) 1936-1947. [99] D. Govorko, R.A. Bekdash, C. Zhang, D.K. Sarkar, Male germline transmits fetal alcohol adverse effect on hypothalamic proopiomelanocortin gene across generations, Biological psychiatry, 72 (2012) 378-388. [100] A. Finegersh, G.E. Homanics, Paternal alcohol exposure reduces alcohol drinking and increases behavioral sensitivity to alcohol selectively in male offspring, PLoS One, 9 (2014) e99078. [101] B. Yu, Y. Qi, D. Liu, X. Gao, H. Chen, C. Bai, Z. Huang, Cigarette smoking is associated with abnormal histone-to-protamine transition in human sperm, Fertility and sterility, 101 (2014) 51-57 e51. [102] M.F. Hamad, N. Shelko, S. Kartarius, M. Montenarh, M.E. Hammadeh, Impact of cigarette smoking on histone (H2B) to protamine ratio in human spermatozoa and its relation to sperm parameters, Andrology, 2 (2014) 666-677. [103] B. Siddeek, N. Lakhdari, L. Inoubli, R. Paul-Bellon, V. Isnard, E. Thibault, A. Bongain, D. Chevallier, E. Repetto, M. Trabucchi, J.F. Michiels, C. Yzydorczyk, U. Simeoni, M. Urtizberea, C. Mauduit, M. Benahmed, Developmental epigenetic programming of adult germ cell death disease: Polycomb protein EZH2-miR101 pathway, Epigenomics, 8 (2016) 1459-1479.

17

M

A

N

U

SC RI PT

[104] J.N. Filkowski, Y. Ilnytskyy, J. Tamminga, I. Koturbash, A. Golubov, T. Bagnyukova, I.P. Pogribny, O. Kovalchuk, Hypomethylation and genome instability in the germline of exposed parents and their progeny is associated with altered miRNA expression, Carcinogenesis, 31 (2010) 1110-1115. [105] Y. Wei, C.R. Yang, Y.P. Wei, Z.A. Zhao, Y. Hou, H. Schatten, Q.Y. Sun, Paternally induced transgenerational inheritance of susceptibility to diabetes in mammals, Proceedings of the National Academy of Sciences of the United States of America, 111 (2014) 1873-1878. [106] N.O. McPherson, J.A. Owens, T. Fullston, M. Lane, Preconception diet or exercise intervention in obese fathers normalizes sperm microRNA profile and metabolic syndrome in female offspring, American journal of physiology. Endocrinology and metabolism, 308 (2015) E805-821. [107] A. Ashe, A. Sapetschnig, E.M. Weick, J. Mitchell, M.P. Bagijn, A.C. Cording, A.L. Doebley, L.D. Goldstein, N.J. Lehrbach, J. Le Pen, G. Pintacuda, A. Sakaguchi, P. Sarkies, S. Ahmed, E.A. Miska, piRNAs can trigger a multigenerational epigenetic memory in the germline of C. elegans, Cell, 150 (2012) 88-99. [108] S. Yuan, A. Schuster, C. Tang, T. Yu, N. Ortogero, J. Bao, H. Zheng, W. Yan, Sperm-borne miRNAs and endo-siRNAs are important for fertilization and preimplantation embryonic development, Development, 143 (2016) 635-647. [109] C. Zhao, J. Dong, T. Jiang, Z. Shi, B. Yu, Y. Zhu, D. Chen, J. Xu, R. Huo, J. Dai, Y. Xia, S. Pan, Z. Hu, J. Sha, Early second-trimester serum miRNA profiling predicts gestational diabetes mellitus, PLoS One, 6 (2011) e23925. [110] R. Rupaimoole, F.J. Slack, MicroRNA therapeutics: towards a new era for the management of cancer and other diseases, Nat Rev Drug Discov, 16 (2017) 203-222. [111] L. Kehler, O. Biro, L. Lazar, J. Rigo, Jr., B. Nagy, Elevated hsa-miR-99a levels in maternal plasma may indicate congenital heart defects, Biomed Rep, 3 (2015) 869-873. [112] B. Siddeek, L. Inoubli, N. Lakhdari, P.B. Rachel, K.C. Fussell, S. Schneider, C. Mauduit, M. Benahmed, MicroRNAs as potential biomarkers in diseases and toxicology, Mutat Res Genet Toxicol Environ Mutagen, 764-765 (2014) 46-57.

A

CC

EP

TE

D

Figure Caption

18

nd

Alterations in region regulating DRD4 and TNXB associated with schizophrenia and bipolar disorders

139 regions hypomethylated and 8 regions hypermethylated,

[92]

Increased genome instability and DNA strand breaks

X-ray

mous e

Alterations in fetal liver

cocaine

mous e

delayed acquisition

ethanol

mous e

reduced ethanol preference and consumption, enhanced sensitivity to the anxiolytic and motorenhancing effects of ethanol

footshock

mous e

CC

Trauma (war)

Alterations in H19 expression increased Bdnf expression in the medial prefrontal cortex

U

carcinogenesis in thymus

N

huma n

SC RI PT

Referen ce

mous e

maternal separation

A

Epigenetic modifications in sperm

Ionizing radiation

EP

STRESS

Cellular mechanisms

DNA methylation, decreased levels of DNMTs and MeCP2 Alteration in H19 gene methylation Increased acetylated histone H3 in Bdnf promoter

[35]

[10]

[29]

increased Bdnf expression in the ventral tegmental area

decreased DNA methylation at the Bdnf promoter

[100]

nd

nd

[30]

mous e

depressive-like behaviors, insulin hypersensitivity, hypermetabolis m

Decreased levels of Ctnnb1 involved in stress pathways

miR-375-3p, miR-375-5p, miR-200b-3p, miR-672-5p and miR-466-5p upregulated downregulatation of piRNAs cluster 110

[31]

Hum an cohor t

depressive symptoms

nd

nd

[18]

Altered methylation in the frontal cortex and hippocampus

nd

[32]

increased expression of glucocorticoidresponsive genes in

Increased miR193-5p, miR204, miR-29c,

[33]

A

TOXICAN TS

Offspring phenotype

M

RADIATI ONS

Ageing

Mod el

D

PHYSIOL OGICAL

Paternal challenge

reduced body weight in female

TE

Type of challenge

Stress (elevated platform)

rat

chronic variable stress

rat

Delay in the acquisition of tasks, reduction in stress reactivi ty reduced HPA str ess axis responsivity

19

the paraventricular nucleus

behavioral sensitivity to the conditioned odor

enhanced neuroanatomical representation of the Olfr151pathway

Under nutrition

Hum an cohor t

higher weights and BMIs

nd

Diet change (more or less food)

Hum an cohor t

Cardiovascular diseases, mortality

nd

Mous e

hypotension, elevated heart rate, vascular dysfunction, impaired glucose tolerance, elevated adiposity, and elevated circulating TNFα levels

[13]

nd

[15]

nd

[14]

decrease in H3K27me3

[25]

U

nd

Mous e

Hepatic alterations

increased expression of genes involved in lipid and cholesterol biosynthesis and decreased levels of cholesterol esters

mous e

Birth defects, developmental abnormalities

Altered expression of genes implicated in the regulation of gene transduction/cell signalling

CC

EP

TE

Low-Protein Diet

D

M

Low-Protein Diet

Decrease of genes involved in calcium signalling and metabolism: Adcy, Plcb, Prkcb, Fto in heart and liver

N

DISTRESS

[34]

A

DIETARY

hypomethylation in the Olfr151 gene

SC RI PT

Odor fear

mous e

miR-30a, miR30c, miR-32, miR-375, miR532–3p, and miR-698

A

Low-folate

High-Fat Diet

rat

obesity and insulin resistance

Testicular alterations in genes involved in nitric oxide and ROS pathways, Sertoli cell junction, EIF2, NF-κβ signalling, inflammatory response, lipid metabolism, and

Alterations in H3K4,K9 methylation, H3K9 trimethylation, altered methylation Altered DNA methylation; miR-133b-3p, miR-196a-5p, miR-205-5p

[26]

[22]

20

carbohydrate metabolism

Prediabetes

mous e

Alterations in genes controlling pancreatic islets (Pik3r1, Pik3ca and Ptpn1)

Alterations in DNA methylation regulating Pik3r1, Pik3r1 and Pik3ca

[105]

SC RI PT

METABO LIC

Glucose intolerance and insulin resistance

Table 1: Studies highlighting paternal exposure to challenges and offspring phenotype

A

CC

EP

TE

D

M

A

N

U

nd: not determined

21