scholarly journals Xenografting of testicular tissue pieces: 12 years of an in vivo spermatogenesis system

Reproduction ◽  
2014 ◽  
Vol 148 (5) ◽  
pp. R71-R84 ◽  
Author(s):  
Lucía Arregui ◽  
Ina Dobrinski
Keyword(s):  
Mammalian Species ◽  
Testicular Tissue ◽  
Recipient Mouse ◽  
Functional Communication ◽  
Young Males ◽  
Complex Process ◽  
Donor Species ◽  
Testis Tissue

Spermatogenesis is a dynamic and complex process that involves endocrine and testicular factors. During xenotransplantation of testicular tissue fragments into immunodecifient mice, a functional communication between host brain and donor testis is established. This interaction allows for the progression of spermatogenesis and recovery of fertilisation-competent spermatozoa from a broad range of mammalian species. In the last few years, significant progress has been achieved in testis tissue xenografting that improves our knowledge about the factors determining the success of grafting. The goal of this review is to provide up to date information about the role of factors such as donor age, donor species, testis tissue preservation or type of recipient mouse on the efficiency of this technique. Applications are described and compared with other techniques with similar purposes. Recent work has demonstrated that testicular tissue xenografting is used as a model to study gonadotoxicity of drugs and to obtain sperm from valuable young males.

Embryo biotechnology in the dog: a review

2010 ◽  
Vol 22 (7) ◽  
pp. 1049 ◽  
Author(s):  
Sylvie Chastant-Maillard ◽  
Martine Chebrout ◽  
Sandra Thoumire ◽  
Marie Saint-Dizier ◽  
Marc Chodkiewicz ◽  
...  
Keyword(s):  
Mammalian Species ◽  
Embryonic Stem ◽  
Reproductive Technologies ◽  
Reproductive Physiology ◽  
Biological Models ◽  
The Past ◽  
Fertilisation Rate

Canine embryos are a scarce biological material because of difficulties in collecting in vivo-produced embryos and the inability, to date, to produce canine embryos in vitro. The procedure for the transfer of in vivo-produced embryos has not been developed adequately, with only six attempts reported in the literature that have resulted in the birth of 45 puppies. In vitro, the fertilisation rate is particularly low (∼10%) and the incidence of polyspermy particularly high. So far, no puppy has been obtained from an in vitro-produced embryo. In contrast, cloning of somatic cells has been used successfully over the past 4 years, with the birth of 41 puppies reported in the literature, a yield that is comparable to that for other mammalian species. Over the same period, canine embryonic stem sells and transgenic cloned dogs have been obtained. Thus, the latest reproductive technologies are further advanced than in vitro embryo production. The lack of fundamental studies on the specific features of reproductive physiology and developmental biology in the canine is regrettable in view of the increasing role of dogs in our society and of the current demand for new biological models in biomedical technology.

Characterization of the reproductive effects of the anorexigenic VGF-derived peptide TLQP-21: in vivo and in vitro studies in male rats

2011 ◽  
Vol 300 (5) ◽  
pp. E837-E847 ◽  
Author(s):  
Leonor Pinilla ◽  
Rafael Pineda ◽  
Francisco Gaytán ◽  
Magdalena Romero ◽  
David García-Galiano ◽  
...  
Keyword(s):  
Chronic Administration ◽  
Testicular Tissue ◽  
Male Rats ◽  
Central Administration ◽  
Adult Males ◽  
Hpg Axis ◽  
Reproductive Effects

VGF (nonacronymic) is a 68-kDa protein encoded by the homonymous gene, which is expressed abundantly at the hypothalamus and has been involved in the control of metabolism and body weight homeostasis. Different active peptide fragments are generated from VGF, including TLQP-21. Circumstantial evidence has suggested that VGF might also participate in the control of reproduction. Yet its mechanisms of action and the eventual role of specific VGF-derived peptides on the hypothalamic-pituitary-gonadal (HPG) axis remain unknown. Herein we report a series of studies on the reproductive effects of TLQP-21 as evaluated in male rats by a combination of in vivo and in vitro analyses. Central administration of TLQP-21 induced acute gonadotropin responses in pubertal and adult male rats, likely via stimulation of GnRH secretion, as documented by static incubations of hypothalamic tissue. In addition, in pubertal (but not adult) males, TLQP-21 stimulated LH secretion directly at the pituitary level. Repeated central administration of TLQP-21 to pubertal males subjected to chronic undernutrition was able to ameliorate the hypogonadotropic state induced by food deprivation. In contrast, chronic administration of TLQP-21 to fed males at puberty resulted in partial desensitization and puberty delay. Finally, in adult (but not pubertal) males, TLQP-21 enhanced hCG-stimulated testosterone secretion by testicular tissue in vitro. In summary, our data are the first to document a complex and multifaceted mode of action of TLQP-21 at different levels of the male HPG axis with predominant stimulatory effects, thus providing a tenable basis for the (direct) reproductive role of this VGF-derived peptide.

ADF/n-cofilin–dependent actin turnover determines platelet formation and sizing

Blood ◽  
2010 ◽  
Vol 116 (10) ◽  
pp. 1767-1775 ◽  
Author(s):  
Markus Bender ◽  
Anita Eckly ◽  
John H. Hartwig ◽  
Margitta Elvers ◽  
Irina Pleines ◽  
...  
Keyword(s):  
Actin Filament ◽  
Molecular Mechanisms ◽  
Critical Role ◽  
Actin Dynamics ◽  
Complex Process ◽  
First Time ◽  
Late Stages ◽  
Platelet Formation

Abstract The cellular and molecular mechanisms orchestrating the complex process by which bone marrow megakaryocytes form and release platelets remain poorly understood. Mature megakaryocytes generate long cytoplasmic extensions, proplatelets, which have the capacity to generate platelets. Although microtubules are the main structural component of proplatelets and microtubule sliding is known to drive proplatelet elongation, the role of actin dynamics in the process of platelet formation has remained elusive. Here, we tailored a mouse model lacking all ADF/n-cofilin–mediated actin dynamics in megakaryocytes to specifically elucidate the role of actin filament turnover in platelet formation. We demonstrate, for the first time, that in vivo actin filament turnover plays a critical role in the late stages of platelet formation from megakaryocytes and the proper sizing of platelets in the periphery. Our results provide the genetic proof that platelet production from megakaryocytes strictly requires dynamic changes in the actin cytoskeleton.

ROLE OF DEHYDROEPIANDROSTERONE AND ITS SULPHATE IN SYNTHESIS OF TESTOSTERONE BY HUMAN TESTES IN VIVO AND IN VITRO

1970 ◽  
Vol 46 (1) ◽  
pp. 21-28 ◽  
Author(s):  
M. C. RAHEJA ◽  
O. J. LUCIS
Keyword(s):  
Free Testosterone ◽  
Testicular Tissue ◽  
Dehydroepiandrosterone Sulphate ◽  
Venous Plasma

SUMMARY The synthesis of testosterone from [4-14C]dehydroepiandrosterone (DHEA) and [7α-3H]dehydroepiandrosterone sulphate (DHEA-S) by human testes in vivo and in vitro was investigated. Neither free testosterone nor free DHEA was found in a perfused testis or the spermatic venous plasma after the infusion of [7α-3H]DHEA-S into the spermatic artery in vivo, whereas 3H-labelled free DHEA, testosterone and androstenedione were isolated after incubation of testicular tissue with the same substrate in vitro. Only 14C-labelled testosterone was found in the spermatic venous effluent and in the testis after infusion of a mixture of equimolar amounts of [7α-3H]-DHEA-S and [4-14C]DHEA into the spermatic artery in vivo. Testosterone containing 3H and 14C was isolated after incubation of testicular tissue with a mixture of the two substrates in vitro.

Defective spermatogenesis and testosterone levels in kinase suppressor of Ras1 (KSR1)-deficient mice

2019 ◽  
Vol 31 (8) ◽  
pp. 1369
Author(s):  
Elena Moretti ◽  
Giulia Collodel ◽  
Giuseppe Belmonte ◽  
Daria Noto ◽  
Emanuele Giurisato
Keyword(s):  
Molecular Mechanisms ◽  
Sperm Concentration ◽  
Testicular Tissue ◽  
Seminiferous Tubules ◽  
Interstitial Tissue ◽  
Testosterone Levels ◽  
Transmission Electron ◽  
Human Spermatogenesis ◽  
Testis Tissue

The aim of this study was to clarify the role of the protein kinase suppressor of Ras1 (KSR1) in spermatogenesis. Spermatogenesis in ksr1−/− mice was studied in testicular tissue and epididymal spermatozoa by light and transmission electron microscopy and by immunofluorescence using antibodies to ghrelin and 3β-hydroxysteroid dehydrogenase (3β-HSD). Blood testosterone levels were also assessed. ksr1−/− mice showed reduced epididymal sperm concentration and motility as compared with wild-type (wt) mice. Testis tissue from ksr1−/− mice revealed a prevalent spermatogenetic arrest at the spermatocyte stage; the interstitial tissue was hypertrophic and the cytoplasm of the Leydig cells was full of lipid droplets. Ghrelin signal was present in the seminiferous tubules and, particularly, in the interstitial tissue of wt mice; however, in ksr1−/− mice ghrelin expression was very weak in both the interstitial tissue and tubules. On the contrary, the signal of 3β-HSD was weak in the interstitial tissue of wt and strong in ksr1−/− mice. Testosterone levels were significantly increased in the blood of ksr1−/− mice (P<0.05) as compared with wt. The results obtained reveal the importance of the KSR scaffold proteins in the spermatogenetic process. The study of the molecular mechanisms associated with spermatogenetic defects in a mouse model is essential to understand the factors involved in human spermatogenesis.

Xenografting restores spermatogenesis to cryptorchid testicular tissue but does not rescue the phenotype of idiopathic testicular degeneration in the horse (Equus caballus)

2010 ◽  
Vol 22 (4) ◽  
pp. 673 ◽  
Author(s):  
Regina M. Turner ◽  
Rahul Rathi ◽  
Ali Honaramooz ◽  
Wenxian Zeng ◽  
Ina Dobrinski
Keyword(s):  
Mammalian Species ◽  
Equus Caballus ◽  
Testicular Tissue ◽  
Seminiferous Tubules ◽  
Primary Defect ◽  
Normal Testis ◽  
Testis Tissue ◽  
Testicular Degeneration

Spermatogenesis from many mammalian species occurs in fragments of normal testis tissue xenografted to mice. Here we apply xenografting to the study of testicular pathology. Using the horse model, we investigated whether exposure to a permissive extratesticular environment in the mouse host would rescue spermatogenesis in cryptorchid testicular tissue or in tissue affected by idiopathic testicular degeneration (ITD). In cryptorchid tissue, where the extratesticular environment is abnormal, xenografting induced spermatogenesis up to meiosis in a subpopulation of seminiferous tubules. Thus, spermatogonia survive and partially retain their potential to differentiate in cryptorchid horse testes. In contrast, the primary defect in equine ITD is hypothesised to be tissue autologous. In support of this, xenografting did not restore spermatogenesis to tissue affected by ITD, thus confirming that the testis itself is primarily diseased. This outcome was not affected by supplementation of exogenous gonadotropins to the mouse host or by reconstitution of a normal reproductive regulatory axis supplied by functional porcine testicular xenografts. These studies demonstrate the usefulness of xenografting for the study of testicular pathology.

AN ASSESSMENT OF THE POSSIBLE ROLE OF 17α,20α-DIHYDROXY-4-PREGNEN-3-ONE IN THE REGULATION OF TESTOSTERONE SYNTHESIS BY RAT AND RABBIT TESTIS

1974 ◽  
Vol 61 (3) ◽  
pp. 401-410 ◽  
Author(s):  
H. W. A. de BRUIJN ◽  
H. J. van der MOLEN
Keyword(s):  
Venous Blood ◽  
Competitive Inhibitor ◽  
Testicular Tissue ◽  
Seminiferous Tubules ◽  
Interstitial Tissue ◽  
Lyase Activity ◽  
Testosterone Biosynthesis

SUMMARY 17α,20α-Dihydroxy-4-pregnen-3-one is a competitive inhibitor of C17,20-lyase activity in rat testicular tissue in vitro and the significance of this inhibition in vitro was evaluated for testosterone biosynthesis in rat and rabbit testis in vivo. It is concluded that 17α,20α-dihydroxy-4-pregnen-3-one is not involved in the regulation of C17,20-activity in vivo, because it was not possible to detect any 17α,20α-dihydroxy-4-pregnen-3-one in rat and rabbit testicular tissue or in testicular venous blood. If present, the levels are lower than 10 pmol/g testis. Levels of 17α-hydroxyprogester-one are in the order of 50 pmol/g testis. The C17,20-lyase has a higher affinity for 17α-hydroxyprogesterone than for 17α,20α-dihydroxy-4-pregnen-3-one and hence inhibition under in-vivo conditions is not favoured. In rat testes the 20α-hydroxysteroid dehydrogenase activity, which can convert 17α-hydroxyprogesterone to 17α,20α-dihydroxy-4-pregnen-3-one, was found to be mainly (97%) localized in the seminiferous tubules and not at the site of testosterone formation in the interstitial tissue.

scholarly journals MECHANISMS IN ENDOCRINOLOGY: Does circadian and ultradian glucocorticoid exposure affect the brain?

2019 ◽  
Vol 180 (2) ◽  
pp. R73-R89 ◽  
Author(s):  
Konstantinos Kalafatakis ◽  
Georgina M Russell ◽  
Stafford L Lightman
Keyword(s):  
Brain Function ◽  
Mammalian Species ◽  
Circadian Variation ◽  
Stress System ◽  
Cellular Events ◽  
The Central Nervous System ◽  
Preclinical And Clinical Studies

Glucocorticoids are a class of systematically secreted hormones, vital for mammalian life, which are intensively investigated for more than 80 years. They regulate multiple body processes like metabolism, fluid homeostasis, immune and stress system responsivity, as well as brain function. Glucocorticoids have a complex rhythm by which they are released to circulation from the adrenal cortex. The hormone exhibits a circadian variation, with high hormonal levels being secreted just prior and during the active part of the day, and progressively lower and lower amounts being released during the inactive part of it. Underlying this diurnal variation there is a more dynamic, ultradian rhythm composed of frequent episodes of glucocorticoid secretion (hormonal pulses). Accumulating evidence from observational, in silico, in vitro and in vivo, preclinical and clinical studies suggest that both aspects of glucocorticoid rhythmicity are preserved among mammalian species and are important for brain function. The central nervous system is exposed to both aspects of the hormonal rhythm and has developed mechanisms able to perceive them and translate them to differential cellular events, genomic and non-genomic. Thus, glucocorticoid rhythmicity regulates various physiological neural and glial processes, under baseline and stressful conditions, and hormonal dysrhythmicity has been associated with cognitive and behavioural defects. This raises a number of clinical implications concerning (i) glucocorticoid involvement in neuropsychiatric disease and (ii) improving the therapeutic efficacy or expanding the role of glucocorticoid-based treatments in such conditions.

scholarly journals Visualising formation of the ribosomal active site in mitochondria

2021 ◽  
Author(s):  
Viswanathan Chandrasekaran ◽  
Nirupa Desai ◽  
Nicholas O. Burton ◽  
Hanting Yang ◽  
Jon Price ◽  
...  
Keyword(s):  
Stress Responses ◽  
Large Subunit ◽  
Mitochondrial Protein ◽  
Mitochondrial Stress ◽  
Cryo Electron Microscopy ◽  
Complex Process ◽  
Mitochondrial Ribosome ◽  
Peptidyl Transferase Centre

SummaryRibosome assembly is an essential and complex process that is regulated at each step by specific biogenesis factors. Using cryo-electron microscopy, we identify and order major steps in the formation of the highly conserved peptidyl transferase centre (PTC) and tRNA binding sites in the large subunit of the human mitochondrial ribosome (mitoribosome). The conserved GTPase GTPBP7 regulates the folding and incorporation of core 16S ribosomal RNA (rRNA) helices and the ribosomal protein bL36m, and ensures that the PTC base U3039 has been 2′-O-methylated. Additionally, GTPBP7 binds the RNA methyltransferase NSUN4 and MTERF4, which facilitate earlier steps by sequestering H68-71 of the 16S rRNA and allowing biogenesis factors to access the maturing PTC. Consistent with the central role of NSUN4•MTERF4 and GTPBP7 during mitoribosome biogenesis, in vivo mutagenesis designed to disrupt binding of their Caenorhabditis elegans orthologs to the large subunit potently activates mitochondrial stress responses and results in severely reduced viability, developmental delays and sterility. Next-generation RNA sequencing reveals widespread gene expression changes in these mutant animals that are indicative of mitochondrial stress response activation. We also answer the long-standing question of why NSUN4 but not its enzymatic activity, is indispensable for mitochondrial protein synthesis in metazoans.

scholarly journals Exploring Seminal Plasma GSTM3 as a Quality and In Vivo Fertility Biomarker in Pigs—Relationship with Sperm Morphology

Antioxidants ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 741
Author(s):  
Marc Llavanera ◽  
Ariadna Delgado-Bermúdez ◽  
Yentel Mateo-Otero ◽  
Lorena Padilla ◽  
Xavier Romeu ◽  
...  
Keyword(s):  
Antioxidant Enzyme ◽  
Seminal Plasma ◽  
Cell Biology ◽  
Sperm Morphology ◽  
Sperm Quality ◽  
Mammalian Species ◽  
Enzyme Linked Immunosorbent Assay ◽  
Epididymal Maturation

Glutathione S-transferases Mu 3 (GSTM3) is an essential antioxidant enzyme whose presence in sperm has recently been related to sperm cryotolerance, quality and fertility. However, its role in seminal plasma (SP) as a predictor of the same sperm parameters has never been investigated. Herein, cell biology and proteomic approaches were performed to explore the presence, origin and role of SP-GSTM3 as a sperm quality and in vivo fertility biomarker. GSTM3 in SP was quantified using a commercial Enzyme-Linked Immunosorbent Assay (ELISA) kit specific for Sus scrofa, whereas the presence of GSTM3 in testis, epididymis and accessory sex glands was assessed through immunoblotting analysis. Sperm quality and functionality parameters were evaluated in semen samples at 0 and 72 h of liquid-storage, whereas fertility parameters were recorded over a 12-months as farrowing rate and litter size. The presence and concentration of GSTM3 in SP was established for the first time in mammalian species, predominantly synthesized in the epididymis. The present study also evidenced a relationship between SP-GSTM3 and sperm morphology and suggested it is involved in epididymal maturation rather than in ejaculated sperm physiology. Finally, the data reported herein ruled out the role of this antioxidant enzyme as a quality and in vivo fertility biomarker of pig sperm.

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