Interactions between oestrogen and 1α,25(OH)2-vitamin D3 signalling and their roles in

14 Pages·2017·1.75 MB·English

by  Ana Paula Zanatta

Zanattaetal.BasicandClinicalAndrology (2017) 27:10
DOI10.1186/s12610-017-0053-z
REVIEW ARTICLE Open Access
Interactions between oestrogen and
α
1 ,25(OH) -vitamin D signalling and their
2 3
roles in spermatogenesis and spermatozoa
functions
Ana Paula Zanatta1,2, Vanessa Brouard1, Camille Gautier1, Renata Goncalves1,2, Hélène Bouraïma-Lelong1,
Fátima Regina Mena Barreto Silva2 and Christelle Delalande1,3*
Abstract
Oestrogens and 1α,25(OH) -vitamin D (1,25-D ) are steroids that can provideeffects by binding to their receptors
2 3 3
localised inthe cytoplasm and in thenucleusor the plasma membrane respectively inducing genomic and non-
genomic effects. As confirmed notably by invalidation of the genes, coding for their receptors as tested withmice
within vivo and invitro treatments, oestrogens and 1,25-D are regulators of spermatogenesis.Moreover,some
3
functionsofejaculatedspermatozoaasviability,DNAintegrity,motility,capacitation,acrosomereactionandfertilizing
abilityaretargetsforthesehormones.Thestudies conducted on their mechanisms of action, even though not
completelyelicited,haveallowedthedemonstrationofputativeinteractionsbetweentheirsignallingpathwaysthat
areworthexaminingmoreclosely.Thepresentreviewfocusesontheelementsregulatedbyoestrogensand1,25-D
3
inthetestisandspermatozoaaswellastheinteractionsbetweenthesignallingpathwaysofbothhormones.
Keywords:Oestrogen,1α,25(OH) -vitaminD (1,25-D ),Spermatogenesis,Spermatozoa,Steroidreceptors
2 3 3
Résumé
L’œstradioletla1α,25(OH) -vitaminD (1,25-D oucalcitriol)sontrespectivementlaformelaplusactivedesœstrogènes
2 3 3
etlaformehormonalementactivedelavitamineD.Cesstéroïdespeuventexercerleurseffetsbiologiquesaprèsfixation
àdesrécepteurslocalisésdanslecytoplasmeetlenoyau(récepteursditnucléaires)ou par fixation à des récepteurs
localisés à la membrane plasmique (récepteurs membranaires) à l’origine d’effets appelés génomiques et non
génomiques respectivement. Bien que les œstrogènes aient longtemps étéconsidéréscommeuniquementdes
hormonesféminines,denombreuxtravauxontpermisdemontrerleurimportance dans le bon déroulement de la
spermatogenèse et la qualité des gamètes. Demême,la1,25-D estcapablederégulerlesfonctionstesticulaires
3
suggérantsonimportancedanslafertilité.Lesétudesréaliséessurleursmécanismesd’action,bienqu’ilsnesoientpas
complètementélucidés,ontpermisdemettreenévidencedesinteractionsentrelesvoiesdesignalisationdecesdeux
hormones.Cetterevueestcentréesurlesévènementsrégulésparlesœstrogènesetla1,25-D danslestesticulesetles
3
spermatozoïdesetlesinteractionsentreleursvoiesdesignalisation.
Mots-clés:Œstrogènes,1,25(OH) -vitamineD (1,25-D ),Spermatogenèse,Spermatozoïde,Récepteursauxstéroïdes
2 3 3
*Correspondence:[email protected]
1INRA,OeReCa,NormandieUniversity,UNICAEN,14000Caen,France
3LaboratoireŒstrogènes,Reproduction,Cancer(OeReCa),EA2608USC
INRA1377,UniversitédeCaenNormandie,EsplanadedelaPaix,CS14032,
14032CAENcedex5,France
Fulllistofauthorinformationisavailableattheendofthearticle
©TheAuthor(s).2017OpenAccessThisarticleisdistributedunderthetermsoftheCreativeCommonsAttribution4.0
InternationalLicense(http://creativecommons.org/licenses/by/4.0/),whichpermitsunrestricteduse,distribution,and
reproductioninanymedium,providedyougiveappropriatecredittotheoriginalauthor(s)andthesource,providealinkto
theCreativeCommonslicense,andindicateifchangesweremade.TheCreativeCommonsPublicDomainDedicationwaiver
(http://creativecommons.org/publicdomain/zero/1.0/)appliestothedatamadeavailableinthisarticle,unlessotherwisestated.
Zanattaetal.BasicandClinicalAndrology (2017) 27:10 Page2of14
Background undertake different roles in spermatogenesis [7]. In
Spermatogenesis is a complex biological process under addition to the wild type ESR1 mRNA, human germ cells
the control of interplay of autocrine, paracrine and express some transcripts deleted from exon 1 whereas the
endocrine factors. In addition to gonadotropins and human spermatozoa exclusively contain the truncated
androgens, it is now well known that oestrogens could form[8]. Consistently with these results, the presence of a
play a significant role in the regulation of the events of shorter isoform of ESR1 of 46 kDa could be observed on
mammalian spermatogenesis but the mechanisms of humanspermatozoa[8]insteadoftheexpectedsizerecep-
oestrogens effects are not well established (for review tor of 66/67 kDa detected by Aquila et al. [9] and Rago et
[1]). Moreover, some data showed 1α,25(OH) -vitamin al. [10]. Later on, these two forms of 66 and 45 kDa were
2
D (1,25-D ) implications in some events of spermato- both detected by Solakidi et al. [11] (Fig. 1b). Moreover, a
3 3
genesis where 1,25-D could, as well as steroids, act at 29 kDa protein was identified by western blotting in hu-
3
genomic (gene expression regulation) and at non- man sperm membranes [12]. Saunders and collaborators
genomic levels (initiated at the plasma membrane) (for described the expression of two proteins ESR2 in human
review [2]). To this aim, their classical receptors adulttestisassuch:ERβ1(wildtype)andavariantisoform
classified as nuclear receptors could also be localised in of ERβ(hERβcx/2) formed by alternative splicing [13]. The
the cytoplasm or in the plasmatic membrane. So, some two proteins ERβ1 and ERβ2 were retrieved in germ cells,
interactions between the signalling pathways of oestro- which are in keeping with the two proteins of 60 kDa and
gens and 1,25-D could be identified; this suggests the 50 kDa observed in human immature germ cells [8] and
3
existence of common roles in spermatogenesis and ejaculated immature spermatozoa [10]. Whereas no ESR2
spermatozoa functions.Thisreviewisfocused on: protein was detected in human spermatozoa in the earlier
phases [8], a 64 kDa protein was finally detected later on
(i)oestrogen and1,25-D receptors, theirlocalization [11, 14]. ESR1 and ESR2 wereobserved on the tail or/and
3
and signallingpathwaysintesticularcells and in the mid-piece with an additional localization for ESR1
spermatozoa. to the equatorial segment [11, 14] (Fig. 1b). Although the
(ii) oestrogen and1,25-D effects andtheir rolesinthe correspondingproteinscouldnothavebeenobserveduntil
3
eventsofspermatogenesisand maturationof now,nevertheless,wehavealsoidentifiedinrattestissome
spermatozoa. mRNA variants of ESR1 and ESR2. Concerning ESR1, we
(iii)thesignallingpathwaysinteractionsofbothhormones. have shown the presence of the full-length form and of
one isoform with exon 4 deleted. For ESR2, besides the
Considering this data (mainly tested on both rodent wild type, three isoforms were observed: one with exon 3
and human species), it does ultimately provide insight deleted and another with an insertion of 54 nucleotides,
into unresolvedissuesandfutureinvestigations. and the last one with both modifications [15]. In addition
toESR1andESR2,atransmembranereceptorcoupledtoa
Oestrogen protein G: GPER (GPR30: G protein coupled receptor 30)
Oestrogenreceptorsintestisandspermatozoa is able to bind to estradiol and to mediate its effects
Classically, oestrogens produce genomic effects after through a non-genomic pathway (for review [16]). This
their binding to the nuclear receptors ERalpha or ESR1 protein can be found in the mouse spermatogonial cell
and ERbeta or ESR2. However, they can also come and line GC-1 and in the mouse spermatocyte-derived cell
attach to receptors localised on the plasma membrane lineGC-2[17,18] but also in therat primary germ cells
andactivatesome signalling pathways(for review [3]).In PS (pachytene spermatocyte) and RS (round spermatid)
mammalian, both forms ESR1 and ESR2 are retrieved in [4, 5], and in immature rat Sertoli cells [19]. In human
somatic and germ cells in testis and on spermatozoa. testis, GPER was also described in Sertoli cells and
Although some datavalues contradict each other the full germ cells (spermatogonia and spermatocytes) and ex-
length receptors ESR1 and ESR2 can be both found in clusively overexpressed in seminomas, the most fre-
Leydig, Sertoli and germ cells from spermatogonia to quent testicular germ cell cancer [20]. But, then, GPER
spermatids in human and rodents species (Fig. 1a; for was predominantly described in peritubular cells [21]
review [1, 4, 5]). Recently, in situ hybridisation and (Fig. 1a). These results are in part different from data
immunohistochemistry experiments on human testis on GPER gene expression, which was observed weakly
confirmed ESR1 and ESR2 expression in germ cells, in Sertoli cells and higher in interstitial cells [6]. The
ESR1 expression in interstitial cells and ESR2 expression GPER protein of 42 KDa was retrieved on human
in Sertoli cells [6]. In addition, some variants have been spermatozoa, in the mid-piece (Fig. 1b) but its
found. On human beings, six ESR2 mRNA variants, in localization seems to be species dependent [22]. There-
addition to the wild type receptor, are present in testis fore, the three forms of oestrogen receptors are
and their different localisation suggests that they expressed by testicular cells and spermatozoa.
Zanattaetal.BasicandClinicalAndrology (2017) 27:10 Page3of14
Fig.1OestrogenandvitaminDreceptorsinmammaliantesticularcellsandhumanspermatozoa.aDetectionofESR1,ESR2,GPERandVDRin
thedifferenttesticularcelltypes.bLocalizationofESR1,ESR2,GPERandVDRinhumanspermatozoa
Roles,effectsandsignallingpathwaysofoestrogensin To determine the importance of non-classical action of
testisandspermatozoa oestrogen receptor, a mouse model expressing exclusively
KOandgeneoverexpression:micemodelsandmen an ERα mutant (2 aa mutation in the DNA binding
mutations domain) was produced [30]. It allowed us to demonstrate
Some evidence on the role of oestrogens in male fertility that non-ERE-dependent oestrogen pathways are suffi-
came from the data obtained in the mouse knockout cient to rescue the defective spermatogenesis observed in
(KO)model.Especially,whilemalemicedeficientinaro- ERKO mice and play a prominent role in ERα action in
matase (Cyp19KO) were initially fertile, they developed the testis, including pathways that regulate water resorp-
progressive infertility with time. Disruptions of sperm- tion and androgen biosynthesis. Moreover, oestrogen non
atogenesiswereobservedbetween4.5monthsand1year, responsive ERalpha knock-in (ENERKI) mice model
despite no decreases in gonadotropins or androgens. (mutation in the ligand-binding domain) permitted to
Spermatogenesiswasprimarilystoppedatearly spermio- enlighten that oestrogen dependent and independent
genic stages as characterized by an increase in apoptosis oestrogen receptor alpha signalling separately regulate
and the appearance of multinucleated cells, leading to a male fertility, with an essential role for oestrogen inde-
significant reduction in round and elongated spermatids pendent ER signalling to concentrate epididymal sperm
without reduction changes in Sertoli cells and earlier via regulation of efferent ductule fluid reabsorption and a
germ cells. In addition, the presence of Leydig cells necessity of oestrogen-dependent ER signalling for germ
hyperplasia/hypertrophy could be clearly appreciated; cell viability [31]. The first model of ERβKO mice was
presumably as a consequence of increased circulating fertile [32] whereas the ERβKO mice developed by Antal
luteinizing hormone [23]. The ERαKO mice were later in which exon 3 was deleted through Cre/LoxP-
infertile [24] as the ERαβKO mice [25, 26]. Although mediatedexcisionandwhichwasdevoidofanytranscript
spermatogenesis was normal up to 10 weeks, mice pre- downstream exon 3 were sterile. However, these mice
sented disrupted spermatogenesis and later degeneration presented no histopathological abnormalities [33]. Otto
of seminiferous tubules afterwards; this was due to the and collaborators suggest that GPR30 does not mediate
inability to reabsorb luminal fluids [24]. The same oestrogenic responses in reproductive organs in mice as
phenotype was revealed during the experiment on mice GPR30KO mice presented no difference in their litters as
which were deleted from exon 3ofthe Esr1gene lacking compared to wild type mice [34], however there was no
the DNA binding domain and null for ERα (Ex3αERKO descriptionofthespermatogenicprocess.
mice) [27]. Joseph and collaborators have observed that Over-expressions of the Cyp19 gene encoding for
sperm recovered from the epididymis of ERαKO mice aromatase enzyme were conducted and brought to light
revealed abnormal coiled flagellum and increased the in- that transgenic male mice expressing human P450
cidence rate of spontaneous acrosome reactions [28, 29]. aromatase(AROM+)wereinfertile (forreview [35]).
Zanattaetal.BasicandClinicalAndrology (2017) 27:10 Page4of14
Only eight cases of invalidation of aromatase have motility even at a low dose, doses below 10 μg/kg/day
been reported in human beings (for review [36]),[37]. appeared to maintain whilst higher doses reversibly
Among them, some patients presented an impaired disrupted spermatogenesis [50]. Chronic estradiol benzo-
reproductive function characterised by a decrease of ate treated adult rats showed a decrease of pachytene
motilityandthenumberofspermatozoa(forreview[36]). spermatocytes and round spermatids due to high testicu-
Only one case of congenital deficiency in oestrogens was lar oxidative stress, altered serum hormonal levels (LH,
described in human beings, due to a resistance to oestro- FSH and testosterone) and low intra-testicular testoster-
gens consecutive to a punctual mutation of ERα gene, one [51]. The exposure of the adult male rat to a high
which revealed a higher sperm density than normal but a phytoestrogen diet confirmed spermatogenesis disruption
reduction in viability [38]. In human beings, polymor- by increasing germ cell apoptosis [52] (Fig. 2). These ef-
phisms of oestrogen related genes would mainly regulate fects on spermatogenesis, apoptosis and hormone levels
sperm concentration and motility but not sperm morph- were maintained in adults after neonatal exposure [53].
ology [39]. Guardacci and collaborators have observed an Moreover, some works enlightened the possible implica-
inverse correlation between higher TA, repeated in the tion of oestrogens in the regulation of differentiation
promoter region of the ERα gene and the total sperm (spermiogenesis) and thus the quality of the gamete and
number in a group of infertile men, suggesting a possible finally the success of all following steps (epididymal tran-
negative influence on human spermatogenesis [40]. The sit, capacitation, acrosomic reaction) until fertilization of
long TA repeats would enhance oestrogen action [41]. the oocyte. In fact, treatment of adult monkeys with an
The significance of the ERα gene in spermatogenesis and aromatase inhibitor suggests that oestrogens are import-
semen quality was supported by the data of Lazaros and ant for spermatid differentiation [54, 55] (Fig. 2). In ro-
collaborators who observed ERα polymorphisms associ- dents, the first sign of effects (deformation of acrosomal
ated to sperm motility and concentration [42]. Whereas granule and nucleus) of neonatal estradiol administration
the single nucleotide polymorphisms (SNPs) and ERβ wasdetectedinthesteps2-3spermatids[56].Studiescon-
gene mutations don’t seem to be a common cause of ducted in rats by D’Souza group suggest that the elong-
spermatogenesis failure in Indian men [43], Aschim and ationprocessofspermatidsfromsteps8to19isandrogen
collaborators[44]concludedthatsomeSNPsinERβcould dependent whereas differentiation of round spermatids
modulate human spermatogenesis. They observed a from steps 1 to 6 is oestrogen relevant. This can be sub-
frequency of the heterozygous RsaI AG-genotype three stantiated by the fact that 20 μg/kg/day of 17β-estradiol
times higher in infertile men compared to controls [44]. administered for 20 days induced prolonged deficiency of
However, no significant associations were found between testosterone causing an absence of step 9–19 spermatids
ERβ (1082G→A and 1730A→G) polymorphisms and seen and the lack of apoptosis seen in steps 1–6 round
spermconcentrationormotility[42]. spermatids [57]. In all estradiol treated groups, they
observed an elevation of elongated spermatids failure to
Invivotreatments undergo spermiation demonstrating an inhibiting effect
Studies conducted in rodents and primates have shown of exogenous 17β-estradiol on spermiation [58] that
that spermatogenesis is partly under oestrogens control could be due to altered vimentin phosphorylation and
at different levels. In the immature bank vole, exposure reorganization [59]. However, this group observed
to a low dose of estradiol induced acceleration of the that 20 and 100 μg/kg/day of estradiol have a differ-
onset of spermatogenesis, which is blocked by the injec- ent effect on the number of rat elongating and round
tion of anti-oestrogen ICI 182,780. On the other hand, spermatids whereas both induced a significant de-
when males were treated with a high dose of estradiol or crease in 2n cells (somatic and germ cells) and 4n
ICI 182,780, disruption of testicular structure, tubular cells (pachytene spermatocytes) in accordance with cell
atrophy and increased apoptosis of germ cells were ob- apoptosis effect of exogenous estradiol in testis [60]. The
served [45]. Moreover, an improvement of the recrudes-
cence of spermatogenesis in estradiol treated rodents
was observed [46, 47]. The induction of spermatogenesis
by estradiol in hypogonadal (hpg) mice involved an ERα
dependent neuroendocrine mechanism increasing circu-
lating FSH and premeiotic spermatogonia and meiotic
spermatocytes [48]. Neonatal oestrogen administration
to rats induced an increase in the number of spermato-
gonia at day 16 of life [49]. However, experiments
conductedwithadultratsshowedthatestradioleffectsare
Fig.2Oestrogenrolesinmammaliantestis
dose and age dependent. While estradiol reduced sperm
Zanattaetal.BasicandClinicalAndrology (2017) 27:10 Page5of14
observation of abnormal acrosome development in the in round and elongating spermatids in June, in mating
ArKO mouse suggests that acrosome biogenesis could be season [72]. In Siberian Hamster, oestrogens are able to
an oestrogen dependent process [23] (Fig. 2). This induce initiation of spermatogenesis, independently of
hypothesisissupported byhighlevelsofaromataseinthe FSH in photo-regressed adult male [47]. In roe deer
Golgicomplexofthedevelopingspermatid[61]aswellas (Capreolus capreolus) a study showed that oestrogens
the presence of oestrogen receptors in rat spermatids [5, could be implicated in sperm production and in sperm-
15]. The chromatin condensation occurring during atozoa maturation by a regulated expression of ERα [73].
spermiogenesis is also regulated by oestrogen (for review In the wild male ground squirrel (Citellus dauricus
[62]). In fact, the levels of testicular and sperm proteins Brandt) a positive immunoreactivity for aromatase has
implicated in this step (TP1, TP2, P1 and CREMτ) beenevidencedin Leydig and Sertoli cells andall types of
decreased after estradiol treatment [63]. Cacciola and spermatogenic cells only during the breeding season and
collaborators [64] have shown that low 17β-estradiol was absent in the non-breeding season. Authors suggest
levels in CNR1 knockout mice play an important role thatoestrogenscouldplayanimportantroleinspermato-
in regulating chromatin remodelling of spermatids by genesis and testicular recrudescence and regression
interfering with chromatin reorganization. Moreover, process [74]. In stallion, although no arrest of spermato-
oestrogens, by promoting histone displacement and genesisisobserved,thesemenoestrogens/androgensratio
chromatin condensation rescue, were able to effi- andESRexpressiononspermatozoainbreedingseasonis
ciently reduce the greater nuclear length observed in highertothenon-breedingseason[75,76].
Cnr1-/- sperm, a morphological parameter related to
chromatin quality [65]. Invitroexperiments
Knowing that effects of estradiol could implicate dif- The experiences conducted in vitro permitted to precise
ferent oestrogen receptors subtypes, some studies were the events regulated by oestrogens (Fig. 2) and their
conducted with some oestrogen receptor subtype spe- mechanisms of action. Whereas endogenous oestrogens
cific ligands [66, 67]. The over-activation of ERα or ERβ inhibited male germ cell line development in mice dur-
subtype had detrimental effects on the fertility parame- ing perinatal life [77], estradiol stimulated the prolifera-
ters knowing that the two ERs had overlapping and dis- tion of rat gonocytes [78, 79]. There is evidence of the
tinct roles. The activation of ERβ would be notably direct role of oestrogens in preventing germ cell apop-
involved in spermiation process and apoptosis whereas tosis. The protective effects of estradiol observed in cul-
the activation of ERα would be involved in spermiogene- tures of human adult seminiferous tubules develop very
sisregulation(Fig. 2). quickly, indicating a non-genomic action of oestrogens
Pathak and collaborators [68] had observed hypo- [80]. However, estradiol was reported to induce in vitro
methylation at the Igf2-H19 ICR in the spermatozoa of apoptosis of rat spermatogenetic cells via the mitochon-
tamoxifen-treated rats;this wasalso foundin the methy- drial pathway; these elements tend to demonstrate the
lation patterns of this loci in the embryos (Fig. 2). How- directactionofoestrogenintheabsenceoftesticularsom-
ever, further studies from the same group did not aticcellsandwithouttheinterferenceofthehypothalamo-
indicate any changes in the methylation status of other hypophyseal axis [81]. More recently, we were able to
imprintedgenes (DMR) inspermatozoa [69]. observe that estradiol activates the EGFR/ERK signalling
In conclusion, in vivo exposures (anti-aromatase, anti- pathway that modulates the expression of genes involved
oestrogensoroestrogens)demonstratethatitisprobably in the balance between cell proliferation and apoptosis
the balance between oestrogens and androgens which is withinPSandRSpurifiedbyrats’testes[4,5].Oestrogens’
crucial for the ongoing of spermatogenesis and quality effects seem to depend on the cellular environment and
of spermatozoa. In fact, whereas overexposure to estra- estradiol concentration, as we have seen in cultures of
diol or to SERM like tamoxifen can cause deleterious ef- adult rat seminiferous tubules, estradiol at 10-9 M
fects on the male reproductive tract and fertility, expresses a different regulation of cyclins A1 and B1 [82].
estradiol can attenuate the age related decline in sperm- In cultured immature rat Sertoli cells, 17β-estradiol in-
atogenesis[70,71]. duces the translocation of oestrogen receptors ESR1 and
ESR2 to the cell membrane, as well as MAPK3/1 phos-
Seasonalbreeders phorylation and their proliferation [83] whereas the bind-
Some natural models of spermatogenesis arrest are the ing of estradiol to GPER mediates MAPK3/1 activation
seasonal breeders and in several species the synthesis through G protein beta gamma subunits that promote
and somewhat the role of oestrogens have been ex- SRC-mediatedmetalloproteasedependentreleaseofEGFR
plored. In the male black bear (Ursus americanus), the ligands which regulate gene expression involved in apop-
presence of aromatase has been reported at the begin- tosis [19, 84]. The anti-apoptotic effect of 17β-estradiol in
ning of testicular recrudescence in Sertoli cells and then immatureSertolicellswasconfirmedbySimoesetal.[85].
Zanattaetal.BasicandClinicalAndrology (2017) 27:10 Page6of14
17β-estradiolandG1(agonistofGPER)alsoinducePI3K/ effects were reported to be time and species
AKTsignalling pathway activation and CREB phosphoryl- dependent [102] (Table 1) but not involving classical
ation in immature Sertoli cells [84]. A recent publication oestrogen receptors [99]. However, it has been ob-
fromthesamelabsuggeststhatESR1andESR2activation served that oestrogens can inhibit some events in-
by estradiol is respectively involved in proliferation and in duced by progesterone. In fact, estradiol inhibited Ca2+
Sertoli cells differentiation respectively. In fact, from 15- influx and acrosomic reactioninducedbyprogesterone in
day-oldratsE2modulatesSertolicellproliferationthrough human spermatozoa (for review [3]) and hyper-activation
ESR1/NF-kB-mediated increase of CCND1, and cell cycle enhanced by progesterone and melatonin in hamster
exit and differentiation through ESR2/CREB-mediated in- spermatozoa [104, 105]. In human, 17β-estradiol also
crease of CDKN1B, GATA-1 and DMRT1 [86]. Kumar regulated cholesterol efflux, protein tyrosine phosphoryl-
and collaborators used seminiferous tubule culture to ation, motility, and acrosin activity of sperm but the
demonstrate that the genes involved in actin remodelling impact of E2 treatments were reduced or absent in the
(Arpc1b, Evl and Picalm), could also play a role in sper- case of varicocele [14]. Finally, estradiol was also able to
miationandareoestrogen-regulated[87]. regulatelipidandglucosemetabolismofsperm[14].
Spermatozoa 1α,25(OH) Vitamin D (1,25-D )
2 3 3
In addition to spermatogenesis events regulated by oes- VitaminD3receptors
trogens, these hormones could also regulate some func- The vitamin D receptor (VDR), originally identified as a
tions of spermatozoa (Table 1). Knowing that chromatin-associated protein [106] binds 1,25-D with
3
spermatozoa are transcriptionally inactive cells [88], the high affinity and specificity, and is associated to 1,25-D
3
effectsofoestrogenarenon-genomic.Uponestradiolex- classical effects. On the other hand, the main assumption
posure, Aquila and collaborators observed an enhance- isthatrapid responses tothis steroid hormonefirst occur
mentinthe phosphorylationoftheproteinsinthe PI3K/ inthe plasma membrane through a membrane-associated
Akt pathway, some of them involved in cell survival sig- receptor[107].Throughcrystallographystudies,thegroup
nals [9]. However, Bennetts and collaborators observed of Norman [108–110] showed that besides the genomic
noeffectof17β-estradiolonhumanspermatozoaviability binding pocket (VDRnuc), VDR also has an alternative
whereascatecholoestrogenswereabletoinducea signifi- pocket (VDRmem) that could be associated with non-
cant loss of cell viability [89]. In the same way, estradiol genomicresponsesinitiatedintheplasmamembrane.
wasdescribedinducingornotDNAdamage[89,90].17β- Another membrane-associated receptor for 1,25-D
3
estradiolalsostimulatedgoldenhamsterspermatozoamo- has also been described. PDIA3 (protein disulfide isom-
tility [91] whereas it reduced the average path velocity erase family A, member 3) was first isolated from the
(VAP) and the straight-line velocity (VSL) of stallion basal membrane of intestinal epithelial cells of chicks
sperm [92]. In human spermatozoa, only catechol oestro- [107]. It was demonstrated that this receptor could bind
gens (no estradiol) were reported to modify their motility to 1,25-D with high affinity, being first nominated 1,25-
3
[89]althoughitwaspreviouslysaidtoregulatethemposi- MARRS (1,25-D membrane associated rapid response
3
tively[93–95].TheactivationofERK1/2byestradiolcould to steroids). This protein also received other denomina-
be involved in the positive effects of estradiol [95]. It was tions, such as ERp60, ERp57 and GRp58. Later on, it
recently demonstrated that LRH-1, a transcription factor was demonstrated that they were one and the same pro-
locatedinhumanspermhead,couldalsobeimplicatedin tein, each having an identical structure when compared
oestrogen signalling pathway of motility, knowing that to others [111]. Like the classical 1,25-D receptor VDR,
3
oestrogen receptors ESR1 and ESR2 are mainly described PDIA3 is also present in the caveolae at the plasma
onflagellum[9,11,14]andwithouthypothesisofmolecu- membrane[112,113].
lar mechanisms [96]. In vivo mice exposure to increased Vitamin D and all its metabolites, including the steroid
17β-estradiol concentrations caused premature sperm hormone 1,25-D , are conformationly flexible (for review
3
capacitation in the epididymis [97]. This effect was con- [2]). The conformational flexibility (6-s-trans and 6-s-cis)
firmed by an increase of protein tyrosine phosphorylation determinesthesignaltransductionpathwaythathastobe
level after in vitro incubations of epididymal spermatozoa activated and, consequently, the biological response pro-
with 17β-estradiol; but the number of sperm that under- duced by its activation (respectively genomic or non-
wenttheacrosomereactionwaslowerinthisgroup[98]. genomic respectively) [109, 114]. Studies about the
Oestrogens and/or xenooestrogens also stimulated in structure-function of 1,25-D showed that the 6-s-cis
3
vitromouse,human,boarandbovinespermcapacitation analoguevitamin,1α,25-dihydroxylumisterol (JN)canef-
3
[95, 98–102], human, mouse, boar and bovine sperm ficiently induce transcaltachiainintestinal epithelium and
acrosome reaction [95, 99, 102, 103] and the fertiliz- also stimulate Ca2+ uptake in osteosarcoma cell line via
ing ability of mouse sperm suspensions [99]. These VDRmem. This analogue, however, failed to activate the
Zanattaetal.BasicandClinicalAndrology (2017) 27:10 Page7of14
Table1Mammalianspermfunctionsregulatedbysomeselectedoestrogens(17β-estradiol,catecholoestrogens,diethylstilbestrol,
estrone,estriol,ethynylestradiol,genistein)
Molecule Event Species Effect Reference
17β-estradiol(E2) Viability Human Noeffect [89]
ROSproduction Human Noeffect [89]
DNAintegrity Human -/noeffect [89,90]
Motility Human +/noeffect [14,89,91–95]
Goldenhamster +
Stallion -
Capacitation Human,mouse,boar + [14,95,98–100],[102]a[103]
bovine Noeffect
Acrosomereaction Human +/noeffect [92,95,98–100],[102]a[103]
Boar +
Mouse +/-
Bovine,stallion Noeffect
Progesteronestimulatedcalcium Human - [3]
andinducedacrosomereaction
Fertilizingability Mouse + [99]
Lipolyticeffect Human + [14]
Glucosemetabolismandinsulin Human + [14]
secretion
Catecholoestrogens Viability Human -/noeffect [89]
(2OHE2,4OHE2)
ROSproduction Human + [89]
DNAintegrity Human -/noeffect [89]
Motility Human - [89]
Diethylstilbestrol(DES) Viability Human Noeffect [89]
ROSproduction Human + [89]
DNAintegrity Human -/Noeffect [89,90]
Estrone(E1,)Estriol(E3), Capacitation Boar,mouse + [98,101]
Ethynylestradiol(EE2)
Acrosomereaction Boar + [98,101]
Mouse -
Genistein Viability Human Noeffect [89]
ROSproduction Human + [89]
DNAintegrity Human - [90]
Capacitation Human,mouse,boar,bovine + [99,100],[102]a[103]
Acrosomereaction Human,mouse,boar + [99,100],[102]a[103]
Bovine Noeffect
Fertilizingability Mouse + [99]
+:positiveeffect,-:negativeeffectand+/-:positiveandnegativeeffect
aEffectsdependentofthetimeandtheconcentration
ROSreactiveoxygenspecies
DNAdeoxyribonucleicacid
genomic action, and it has shown a very low capacity to between VDR and RXR, and of VDR interaction with co-
bind to VDRnuc [115, 116]. On the other hand, another activator,steroidreceptorco-activator1(SRC-1)[119].
analogue vitamin, the 1β,25-dihydroxyvitamin D (HL) Thepresenceof VDR in several tissues and cellsof the
3
has been proved to block rapid responses induced by male reproductive system has been demonstrated by
1,25-D orJNandisrecognizedasaspecificantagonistof several studies; this could explain the importance of this
3
the non-genomic action [117, 118]. Similarly, the 1,25-D hormone in reproductive tissues. Animal studies have
3
genomic response can be blocked by co-incubation with shown VDR expression in both nucleus and cytoplasm
the analogue vitamin (23S)-25-dehydro-1α(OH)-vitamin in primary cultures of immature rat Sertoli cells and in
D -26,23-lactone (MK), which antagonistic action is immature mice Sertoli cell line TM4 [120–122], semin-
3
caused by the inhibition of heterodimer formation iferous tubules and the caput epididymis [123, 124]. A
Zanattaetal.BasicandClinicalAndrology (2017) 27:10 Page8of14
staining of Leydig cells was also observed for human and diabetic rats. Hamden and collaborators [139] have ob-
mouse [125,126]. VDR is expressed in germ cellsof both served that the administration of 1,25-D 3 weeks before
3
rodents and humans: spermatogonia, spermatocytes and and after diabetes induction prevented oxidative stress,
roundandelongatedspermatids[121,125,126]aswellas toxicity and hypo-fertility in diabetic rat testes. Finally, it
insperm[127,128]butSertolicellsarestillconsideredto has been shown that vitamin D treatment up-regulates
bethe main 1,25-D target in the adult testis[2](Fig. 1a). some testis-specific genes in cryptorchid mouse testis
3
Previous studies have shown that, after injection of [3H]- whereby 19 out of 2483 testis-specific genes showed up-
1,25(OH) -vitamin D (soltriol), the nuclear labelling is regulationby1,25-D treatment[124].
2 3 3
foundinSertolicells,andisthehighestoneproportionally
totheseminiferoustubulesinwhichresidualbodiesinthe Invitrotreatments
apical part are distinctly stained [129]. ERp57, before be- As observed in osteoblasts notably by Enjuanes et al.
ing described as a vitamin D receptor, was investigated in [140],weobservedthat1,25-D isabletostimulatetheex-
3
human testis and spermatozoa. ERp57 was located in pression of Cyp19, the gene which encodes the enzyme
spermatocytes to spermatozoa and Leydig cells; a faint la- P450aromatase,inimmatureratSertolicells[121].Mena-
belling was also observed in Sertoli cells [130] (Fig. 1). In gaz et al. [141] reported that 1,25-D plays an important
3
the rat testis, PDIA3 is also present in Leydig and germ roleintestisthroughgenomiceffectsthatcanbetriggered
cells (from spermatogonia to spermatozoa). PDIA3 pro- by protein kinase A, as well as by rapid responses (amino
tein was observed on the entire membrane of rat sperm- acid accumulation) involving Ca2+/K+ channels on the
−
atozoaandintheacrosome[131]. plasmamembraneandstimulatingexocytosisviaCl chan-
Spermatozoa arehighly compartmentalized cells, and all nel activation in the Sertoli cell line TM4 [120]. Other
studies investigating VDR expression in mature human studies demonstrated that 1,25-D triggers plasma
3
spermatozoa showed VDR expression in the post- membrane-initiatedactionsbymodulatingcalciumuptake
acrosomalpartofthehead,mid-piece,andintheneckre- and by altering gamma-glutamyltranspeptidase (GGTP)
gion (Fig. 1b) [125, 127, 128]. Subcellular VDR expression activity in immature rat testis. GGTP is involved in the
may therefore depend on optimal spermatogenesis and synthesisofspecificproteinsknowntobesecretedbySer-
maturation,becauseincompleteformationofthesubcellu- toli cells[142].Also,Rossoetal. [143]reportedthat1,25-
larcompartmentsmayleadtoanunusuallocalisationand, D activatesp38MAPKandreorganizesmicrotubules,in-
3
potentially,anunusualfunctionofthereceptor[132,133]. volving Ca2+, PKC and ERK1/2 as upstream regulators,
and that extracellular Ca2+ have a central role to rapidly
Roles,effectsandsignallingpathwaysof1,25-D intestis start hormone-induced gene transcription and/or the
3
andspermatozoa secretoryactivityofSertolicells.
KOmicemodelsandinvivotreatments
There is accumulating evidence that 1,25-D and VDR Spermatozoa
3
constitute an important part of the reproductive tissues. In a study investigating human sperm at the molecular
In fact, although the male vitamin D receptor of null level, 1,25-D had an effect on cholesterol efflux, protein
3
mutant mice produced by Erben and collaborators were phosphorylation, and increased sperm survival [128].
fertile [134]; the VDR knockout mice produced by the Thus, 1,25-D might play an important role in the extra
3
group of Kinuta [135] showed gonadal insufficiencies. testicular maturation of sperm by influencing capacita-
Indeed, in the male, decreased sperm count and de- tion and might modulate sperm survival. Also, Aquila et
creased motility with histological abnormality of the al. [144] demonstrated that 1,25-D through VDR
3
testis were observed [135]. This difference may be re- increased intracellular Ca2+ levels, motility, and acrosin
lated to a different genetic background [134]. Early stud- activity, and reduced triglyceride content in sperm, re-
ies in vitamin D-deficient male rats have shown that, vealing an effect of 1,25-D in the acquisition of fertiliz-
3
even if they are able to reproduce themselves, animals ing ability in human sperm. Moreover, 1,25-D increased
3
have a 45% reduction in successful mattings as well as a sperm motility and induced acrosome reaction [145].
decreased overall fertility rate that is reduced by 73% 1,25-D effect on motility was dependent on the charac-
3
when compared to controls [136]. The testes of vitamin teristics of samples as 1,25-D significantly increased
3
D-deficient ratsshowed incomplete spermatogenesis and spermatozoa motility in young men but was unable to
degenerative changes [137]. The fertility of vitamin D dosoinspermatozoafrom sub-fertilemen[133].
deficient male rats is restored by treatment with vitamin
D and its active metabolite 1,25-dihydroxycholecalciferol Interactions between oestrogens and 1,25-D
3
but their effect is indirect as fertility is also restored by a signalling pathways
diet supplemented with high levels of calcium [138]. Asreportedbefore,oestrogensand1,25-D couldregulate
3
1,25-D also had some protective actions in testis of spermatogenesis or spermatozoa’s maturation, suggesting
3
Zanattaetal.BasicandClinicalAndrology (2017) 27:10 Page9of14
possible interactions between their signalling pathways. productioninLnCapandNCI-H295R.Nevertheless,itin-
This idea is, in fact, supported by some already published duced a significant increase of estradiol production in
data (Fig. 3). First, both hormones’ respective receptors NCI-H295R in presence of additional androstenedione
could be expressed by the same cells (testicular cells and [152]. 1,25-D also had a positive effect in estradiol pro-
3
spermatozoa)(Fig.1).Then,VDRablationwasresponsible duction in osteosarcoma and ovarian cancer cells, but re-
for oestrogen deficiency and abnormal spermatogenesis sulted a negative effect in oestrogen receptor-positive
observed in VDRKO mice whereas oestrogensupplemen- breastcancer(BCa)cellsandadipocytes[153].Aromatase
tation protected the testis of histological abnormality downregulationby1,25-D inBCacellswasduetoadir-
3
[135]. Moreover, a significantly lower ERβ expression was ect repression of aromatase transcription via promoter II
found in testis of Vdr+/- and Vdr-/- Leuven strain mice throughthevitaminD-responseelementsidentifiedinthis
withoutchangesinthehistologyofthetestiswhereasepi- promoter and an indirect suppression by reducing the
didymal expression of ERα and the oestrogen target gene levelsofprostaglandins[153].Itisinterestingtonotethat
Aqp9 were higher [146]. 1,25-D reduced significantly the Cyp19 expression in male gonad is in part driven by the
3
levels of the steroid receptors (ERα, PRA and PRB) in promoter PII (for review [154]). The analogue vitamin D
human uterine leiomyoma (HuLM) cells, regulated posi- EB1089 is also able to decrease Cyp19 gene expression
tively the levels of its receptor (VDR) and inhibited and aromatase activity and to inhibit the aromatase
oestrogen induced proliferation of cultured (HuLM) cells dependent cell growth of breast cancer cells [155]. In rat
suggesting that 1,25-D could function as anti- granulosacells,1,25-D reducedtestosteroneinducedaro-
3 3
oestrogenic/progesteronicagent[147]. matase expression butimproved 17β-estradiol production
1,25-D could also regulate seric steroid levels and not- by a calcium dependent pathway [156]. In human
3
ably estradiol levels. In fact, 1,25-D positively regulated activated macrophages, 1,25-D may downregulate the
3 3
Cyp19 expression in immature rat Sertoli cells [121] as pro-inflammatory cytokine production by significantly
previously observed in human osteoblasts [140, 148]. Es- decreasingthearomataseactivity,especiallyinpresenceof
tradiol production of rat costochondral chondrocytes an estrogenic milieu [157]. In HEK-293, ERK1/2 phos-
[149]andaromataseactivityofhumanmesenchymalstem phorylation and up regulation of VDR protein expression
cells [150] and prostate cancer cells [151] are stimulated induced by estradiol required the association of ERβ to
by vitamin D. However, 1,25-D effect on oestrogen me- plasma membrane caveolae components [158]. 1,25-D is
3 3
tabolismistissuespecific.Admittedlyithadanegativeef- able to restore the expression of a functional ERα in ER
fect on aromatase expression and estradiol production in negative breast cancer cells probably by a transcriptional
MCF-7 cells, whereas it had no effect on estradiol VDR dependent regulation, as the ER promoter contains
Fig.3Interactionsbetweengenomicandnongenomicactionof1,25-D andoestrogens.1,25-D canbindVDRlocalizedattheplasmamembraneor
3 3
intracellularVDRandcouldregulateCyp19andERαgeneexpression,aromataseactivityandestradiolproduction.EstradiolcanregulateVDRgene
expressionbyESR2localizedattheplasmamembraneandCyp19geneexpression.E2:estradiol,1,25-D:1α,25dihydroxyvitaminD,ESR1/2:estrogen
3 3
receptor1and2,GPER:Gproteincoupledestrogenreceptor,VDRmem:vitaminDreceptorlocalizedattheplasmamembrane,VDRnuc:nuclearvitamin
Dreceptor,VDRE:vitaminDresponsiveelement,ERE:oestrogenresponsiveelement
Zanattaetal.BasicandClinicalAndrology (2017) 27:10 Page10of14
several putative vitamin D response elements [159]. 1,25- Boisen and collaborators in 2016 [171] indicated that
D also regulates androgen production, the aromatase other studies (notably high quality randomized con-
3
substrate, in a tissue specific manner [152, 160, 161]. It trolled trials) would be necessary to evaluate the effect
was interesting to note a testosterone level increase in a of vitamin D supplementation on the improvement of
group of men who received vitamin D supplementation semen qualityandsubsequently onfertility.
[160]. 1,25-D had a protective effect on alloxan-induced
3
Abbreviations
damage in reproductive system by enhancing the testos-
1,25-D:1α,25(OH)-vitaminD;E:Estradiol;ESR:Estrogenreceptor;GPER:G
terone and 17β-estradiol levels consequently protecting protein3-coupledes2trogenrece3pto2r;PS:Pachytenespermatocyte;RS:Round
fromoxidativestress,cellulartoxicityandmaintainingthe spermatid;VDR:VitaminDreceptor;VDRmem:VDRlocalizedattheplasma
membrane;VDRnuc:VDRlocalizedinthenucleus
numberandmotilityofspermatozoids[139].Matsudaand
collaborators have also demonstrated that the effects of Acknowledgements
oestrogen on mouse vaginal development are influenced WearegratefultoCélineQuintofthe“centredetraduction”,UniversitéCaen
NormandieforEnglishrevision.
by 1,25-D [162]. Finally, it was observed that in a redu-
3
cingenvironment,estradiolcompetedforbindingto1,25-
Funding
D3-MARRS receptor/PDIA3/ERp57 and was able to ThisworkwassupportedbytheNationalInstituteofResearchinAgronomy
stimulatedcalciumuptakeinisolatedenterocytes[163]. (INRA)andbytheFrenchMinistryofEducationandResearch.AnaPaula
ZanattaandRenataGonçalveswerebenefitedofPhDfellowshipfromCNPq-
Therefore, in testicular cells and in spermatozoa, vita-
SciencewithoutbordersBrazil(Process#236866/2012-5and204568/2014-5),
min D could modulate oestrogen non-genomic effects CamilleGautierfromtheMESRandVanessaBrouardwasfundedbytheLow
but alsotheirgenomiceffectsandreciprocally. NormandyRegionalCouncil(CRBN).
Availabilityofdataandmaterials
Conclusions Notapplicable.
To conclude, we assume that common testicular cells
Authors’contributions
and spermatozoa express oestrogen receptors (ESR) and
APZandCDwrotethemanuscript.VB,CG,HBL,RGandFRMBScritically
1,25-D3 receptors (VDR); moreover, in vitro and in vivo revisedthemanuscript.Allauthorshaveapprovedthefinalmanuscript.
studies suggest that oestrogens and 1,25-D play roles in
3
spermatogenesis and spermatozoa functions. However, Competinginterests
Theauthorsdeclarethattheyhavenocompetinginterests.
the mechanisms involved in the regulation of the events
under 1,25-D and 17β-estradiol control; and their pos- Consentforpublication
3
Notapplicable.
sible interactions could not be completely identified. In-
deed, even if the recent review published by Blomberg
Ethicsapprovalandconsenttoparticipate
Jensen [164] also indicated a relation between VDR and Notapplicable.
oestrogen in the male reproductive organs, there were
few data about dialogue mechanisms between oestrogen Publisher’s Note
and vitamin D signalling pathways. Some data obtained SpringerNatureremainsneutralwithregardtojurisdictionalclaimsinpublished
mapsandinstitutionalaffiliations.
in numerous cell types suggest that calcium could play
an intermediate role in non-genomic effects, notably in Authordetails
spermatozoa but also in other testicular cell types like 1INRA,OeReCa,NormandieUniversity,UNICAEN,14000Caen,France.
germ cells and Leydig cells. In fact, these cells, in which U2BFioSCch,FelmoriisatnryóDpoelpisa,rBtmraezinl.t,3LLaabboorraattooirryeoŒfsHtroorgmèonneess,R&epSirgondaulcTtiroann,sdCuacntcioern,
calcium currents were measured express VDR and ESR (OeReCa),EA2608USCINRA1377,UniversitédeCaenNormandie,Esplanade
[165, 166]. The physiological significance and the spe- delaPaix,CS14032,14032CAENcedex5,France.
cific roles endorsed by these hormones and their recep-
Received:17October2016Accepted:16March2017
tors in human spermatozoa require further investigation.
A better comprehension of the matter could give us in-
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