API

Relationship: 1735

Title

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Apoptosis leads to spermatocyte depletion

Upstream event

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Apoptosis

Downstream event

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spermatocyte depletion

Key Event Relationship Overview

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AOPs Referencing Relationship

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AOP Name Adjacency Weight of Evidence Quantitative Understanding
Histone deacetylase inhibition leading to testicular toxicity adjacent High Not Specified

Taxonomic Applicability

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Term Scientific Term Evidence Link
Mus musculus Mus musculus High NCBI
Rattus norvegicus Rattus norvegicus High NCBI

Sex Applicability

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Sex Evidence
Male High

Life Stage Applicability

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Term Evidence
Adult, reproductively mature High

Key Event Relationship Description

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Apoptosis results in spermatocyte depletion via cell death. HDAC inhibitor, MAA, induced apoptosis and spermatocyte depletion at stages IX-II [Brinkworwth, 1995]. Induced apoptosis during development of germ cells results in progressive depletion of spermatocyte.

Evidence Supporting this KER

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Biological Plausibility

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In the mouse spermatocyte, spermatogenesis was inhibited by knockdown of Sucla2, a b subunit of succinyl coenzyme A synthase, via apoptosis [Huang, 2016]. The prolonged cryptorchidism leads to germs cell apoptosis and testicular sperm count decrease [Barqawi, 2004]. CD147 was reported to regulate apoptosis in mouse testis and spermatocyte cell line (GC-2 cells) via NFκB pathway [Wang, 2017].

Empirical Evidence

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MicroRNA-21 regulates the spermatogonial stem cell homeostasis, in which suppression of microRNA-21 with anti-miR-21 oligonucleotides led to apoptosis of spermatogonial stem cell-enriched germ cell cultures and the decrease in the number of spermatogonial stem cells [Niu, 2011].

Uncertainties and Inconsistencies

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The process of apoptosis is necessary for the meitosis of the stem cell differentiation in the testis, which remains in question for the regulation of spermatocyte deletion and testis atrophy/weight loss [Dym, 1994].

Quantitative Understanding of the Linkage

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The apoptotic germ cells occurred in the Stra8-Cre KO tubules were approximately 68%, whereas 46% of the cells were germ cells in WT tubules, as determined by double staining for Tra98, a germ cell marker, and cleaved caspase 3 [Bose, 2018].

Response-response Relationship

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Time-scale

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Known modulating factors

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Known Feedforward/Feedback loops influencing this KER

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Domain of Applicability

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The relationship between apoptosis and spermatocyte depletion is likely well conserved between species.

  • Spermatogenesis was inhibited by knockdown of Sucla2 via apoptosis in the mouse spermatocyte (Mus musculus) [Huang, 2016].
  • The suppression of microRNA-21 led to apoptosis of spermatogonial stem cell-enriched germ cell cultures and the decrease in the number of spermatogonial stem cells in mice (Mus musculus) [Niu Z, 2011].
  • MAA induced apoptosis and depletion of spermatocytes in adult rats (Rattus norvegicus) [Brinkworth, 1995].

References

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Brinkworth M et al. (1995) Identification of male germ cells undergoing apoptosis in adult rats. J Reprod Fertil 105: 25-33

Huang S et al. (2016) Knockdown of Sucla2 decreases the viability of mouse spermatocytes by inducing apoptosis through injury of the mitochondrial function of cells. Folia Histochem Cytobiol 54: 134-142

Barqawi A et al. (2004) Effect of prolonged cryptorchidism on germ cell apoptosis and testicular sperm count. Asian J Androl 6: 47-51.

Wang C et al. (2017) CD147 regulates extrinsic apoptosis in spermatocytes by modulating NFkB signaling pathways. Oncotarget 8: 3132-3143

Niu Z et al. (2011) microRNA-21 regulates the self-renewal of mouse spermatogonial stem cells. Proc Natl Acad Sci 108: 12740-12745

Dym M. (1994) Spermatogonial stem cells of the testis. Proc Natl Acad Sci USA 91: 11287-11289

Bose R et al. (2017) Ubiquitin ligase Huwe1 modulates spermatogenesis by regulating spermatogonial differentiation and entry into meiosis. Sci Rep 7: 17759