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Relationship: 1713

Title

A descriptive phrase which clearly defines the two KEs being considered and the sequential relationship between them (i.e., which is upstream, and which is downstream). More help

Apoptosis leads to Testicular atrophy

Upstream event

The causing Key Event (KE) in a Key Event Relationship (KER). More help

Apoptosis

Downstream event

The responding Key Event (KE) in a Key Event Relationship (KER). More help

Testicular atrophy

Key Event Relationship Overview

The utility of AOPs for regulatory application is defined, to a large extent, by the confidence and precision with which they facilitate extrapolation of data measured at low levels of biological organisation to predicted outcomes at higher levels of organisation and the extent to which they can link biological effect measurements to their specific causes.Within the AOP framework, the predictive relationships that facilitate extrapolation are represented by the KERs. Consequently, the overall WoE for an AOP is a reflection in part, of the level of confidence in the underlying series of KERs it encompasses. Therefore, describing the KERs in an AOP involves assembling and organising the types of information and evidence that defines the scientific basis for inferring the probable change in, or state of, a downstream KE from the known or measured state of an upstream KE. More help

AOPs Referencing Relationship

Taxonomic Applicability

Latin or common names of a species or broader taxonomic grouping (e.g., class, order, family) that help to define the biological applicability domain of the KER.In general, this will be dictated by the more restrictive of the two KEs being linked together by the KER. More help

Sex Applicability

An indication of the the relevant sex for this KER. More help

Life Stage Applicability

An indication of the the relevant life stage(s) for this KER. More help

Key Event Relationship Description

Provides a concise overview of the information given below as well as addressing details that aren’t inherent in the description of the KEs themselves. More help

In the mouse spermatocyte, spermatogenesis was inhibited by knockdown of Sucla2 via apoptosis (Huang). CD147 was reported to regulate apoptosis in mouse testis and spermatocyte cell line (GC-2 cells) via NFkB pathway (Wang).

Evidence Collection Strategy

Include a description of the approach for identification and assembly of the evidence base for the KER. For evidence identification, include, for example, a description of the sources and dates of information consulted including expert knowledge, databases searched and associated search terms/strings. Include also a description of study screening criteria and methodology, study quality assessment considerations, the data extraction strategy and links to any repositories/databases of relevant references.Tabular summaries and links to relevant supporting documentation are encouraged, wherever possible. More help

Evidence Supporting this KER

Addresses the scientific evidence supporting KERs in an AOP setting the stage for overall assessment of the AOP. More help

Biological Plausibility

Addresses the biological rationale for a connection between KEupstream and KEdownstream. This field can also incorporate additional mechanistic details that help inform the relationship between KEs, this is useful when it is not practical/pragmatic to represent these details as separate KEs due to the difficulty or relative infrequency with which it is likely to be measured. More help

Apoptosis is a basic biological phenomenon in which the cells are controlled in the atrophy of various tissues and organs through the deletion and turnover, as well as in tumor regression (Kerr JFR et al).

Empirical Evidence

Provides specific (citable) evidence that supports the idea of a change in the upstream KE (KEupstream) leading to, or being associated with, a subsequent change in the downstream KE (KEdownstream), assuming the perturbation of KEupstream is sufficient. More help

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 Z et al).

Uncertainties and Inconsistencies

Addresses inconsistencies or uncertainties in the relationship including the identification of experimental details that may explain apparent deviations from the expected patterns of concordance. More help

Spermatogonial stem cell self-renewal and spermatocyte meiosis are regulated by Sertoli cell signaling, which suggests us that various pathways other than HDAC inhibition in spermatocytes or spermatogonia are involved in the spermatocyte deletion and testis atrophy/weight loss (Chen SR). It should be noted that 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 M).

Known modulating factors

This table captures specific information on the MF, its properties, how it affects the KER and respective references.1.) What is the modulating factor? Name the factor for which solid evidence exists that it influences this KER. Examples: age, sex, genotype, diet 2.) Details of this modulating factor. Specify which features of this MF are relevant for this KER. Examples: a specific age range or a specific biological age (defined by...); a specific gene mutation or variant, a specific nutrient (deficit or surplus); a sex-specific homone; a certain threshold value (e.g. serum levels of a chemical above...) 3.) Description of how this modulating factor affects this KER. Describe the provable modification of the KER (also quantitatively, if known). Examples: increase or decrease of the magnitude of effect (by a factor of...); change of the time-course of the effect (onset delay by...); alteration of the probability of the effect; increase or decrease of the sensitivity of the downstream effect (by a factor of...) 4.) Provision of supporting scientific evidence for an effect of this MF on this KER. Give a list of references. More help

Quantitative Understanding of the Linkage

Captures information that helps to define how much change in the upstream KE, and/or for how long, is needed to elicit a detectable and defined change in the downstream KE. More help

The ratio between self-renewal and differentiation of the spermatogonial stem cells is regulated by glial cell line-derived neurotrophic factor produced by Sertoli cells (de Rooij2001). The development of the spermatogenic cell lineage is strictly regulated with 12 epithelial stages, in which G1 arrest is involved (de Rooij1998).

Response-response Relationship

Provides sources of data that define the response-response relationships between the KEs. More help

Time-scale

Information regarding the approximate time-scale of the changes in KEdownstream relative to changes in KEupstream (i.e., do effects on KEdownstream lag those on KEupstream by seconds, minutes, hours, or days?). More help

Known Feedforward/Feedback loops influencing this KER

Define whether there are known positive or negative feedback mechanisms involved and what is understood about their time-course and homeostatic limits. More help

Domain of Applicability

A free-text section of the KER description that the developers can use to explain their rationale for the taxonomic, life stage, or sex applicability structured terms. More help

Spermatogenesis was inhibited by knockdown of Sucla2 via apoptosis in the mouse spermatocyte (Mus musculus) (Huang). 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 et al).

References

List of the literature that was cited for this KER description. More help

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

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

Kerr JFR et al. (1972) Apoptosis: a basic biological phenomenon with wide-ranging implications in tissue kinetics. Br J Cancer 26: 239-257

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

Chen S and Liu Y. (2015) Regulation of spermatogonial stem cell self-renewal and spermatocyte meiosis by Sertoli cell signaling. Reproduction 149: R159-R167

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

De Rooij DG et al. (2001) Proliferation and differentiation of spermatogonial stem cells. Reproduction 121: 347-354

De Rooij DG. (1998) Stem cells in the testis. Int J Exp Path 79: 67-80