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Transcriptome profiling of mice testes following low dose irradiation.

Belling KC, Tanaka M, Dalgaard MD, Nielsen JE, Nielsen HB, Brunak S, Almstrup K, Leffers H - Reprod. Biol. Endocrinol. (2013)

Bottom Line: We separated the transcripts into five unique clusters that we associated with spermatogonia, spermatocytes, early spermatids, late spermatids and somatic cells, respectively.We observed large expression changes in the somatic cell profile, which mainly could be attributed to changes in cellularity, but hyperplasia of Leydig cells may also play a role.We speculate that the possible hyperplasia may be caused by lower testosterone production and inadequate inhibin signalling due to missing germ cells.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Background: Radiotherapy is used routinely to treat testicular cancer. Testicular cells vary in radio-sensitivity and the aim of this study was to investigate cellular and molecular changes caused by low dose irradiation of mice testis and to identify transcripts from different cell types in the adult testis.

Methods: Transcriptome profiling was performed on total RNA from testes sampled at various time points (n = 17) after 1 Gy of irradiation. Transcripts displaying large overall expression changes during the time series, but small expression changes between neighbouring time points were selected for further analysis. These transcripts were separated into clusters and their cellular origin was determined. Immunohistochemistry and in silico quantification was further used to study cellular changes post-irradiation (pi).

Results: We identified a subset of transcripts (n = 988) where changes in expression pi can be explained by changes in cellularity. We separated the transcripts into five unique clusters that we associated with spermatogonia, spermatocytes, early spermatids, late spermatids and somatic cells, respectively. Transcripts in the somatic cell cluster showed large changes in expression pi, mainly caused by changes in cellularity. Further investigations revealed that the low dose irradiation seemed to cause Leydig cell hyperplasia, which contributed to the detected expression changes in the somatic cell cluster.

Conclusions: The five clusters represent gene expression in distinct cell types of the adult testis. We observed large expression changes in the somatic cell profile, which mainly could be attributed to changes in cellularity, but hyperplasia of Leydig cells may also play a role. We speculate that the possible hyperplasia may be caused by lower testosterone production and inadequate inhibin signalling due to missing germ cells.

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The median z-scaled gene expression of the five transcript clusters during recovery from irradiation. The clusters are coloured as following: Blue: Spermatogonia (cluster 1); Red: Spermatocytes (cluster 2); Green: Early spermatids (cluster 3); Brown: Late spermatids (cluster 4); Purple: Somatic cells (cluster 5).
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Figure 2: The median z-scaled gene expression of the five transcript clusters during recovery from irradiation. The clusters are coloured as following: Blue: Spermatogonia (cluster 1); Red: Spermatocytes (cluster 2); Green: Early spermatids (cluster 3); Brown: Late spermatids (cluster 4); Purple: Somatic cells (cluster 5).

Mentions: To add further evidence of the association of cell types to the clusters, we identified previously published cell-specific markers in the five clusters [16-18]. In total, 39 markers were identified in the five clusters representing spermatogonia (n = 1), spermatocytes (n = 19), spermatids (n = 11), Leydig cells (n = 3), PTM cells (n = 1), and Sertoli cells (n = 4) (Table 1, Figure 1 and Figure 2). The single marker associated with spermatogonia was found in the corresponding cluster (cluster 1). The spermatocyte markers were evenly distributed in all five clusters, but comparing the expression patterns to the profiles identified earlier [10,16] strongly indicated that this cluster (cluster 2) with a reduced expression at pi day 17, mainly contained transcripts from spermatocytes. Most spermatid markers were present in the two clusters that we associated with early and late spermatids (cluster 3 and 4). The transcripts in the somatic cell cluster contained all somatic cell markers (cluster 5), which confirmed that the cluster represented all somatic cells and not only transcripts from Sertoli cells as suggested in our earlier study [10].


Transcriptome profiling of mice testes following low dose irradiation.

Belling KC, Tanaka M, Dalgaard MD, Nielsen JE, Nielsen HB, Brunak S, Almstrup K, Leffers H - Reprod. Biol. Endocrinol. (2013)

The median z-scaled gene expression of the five transcript clusters during recovery from irradiation. The clusters are coloured as following: Blue: Spermatogonia (cluster 1); Red: Spermatocytes (cluster 2); Green: Early spermatids (cluster 3); Brown: Late spermatids (cluster 4); Purple: Somatic cells (cluster 5).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3672050&req=5

Figure 2: The median z-scaled gene expression of the five transcript clusters during recovery from irradiation. The clusters are coloured as following: Blue: Spermatogonia (cluster 1); Red: Spermatocytes (cluster 2); Green: Early spermatids (cluster 3); Brown: Late spermatids (cluster 4); Purple: Somatic cells (cluster 5).
Mentions: To add further evidence of the association of cell types to the clusters, we identified previously published cell-specific markers in the five clusters [16-18]. In total, 39 markers were identified in the five clusters representing spermatogonia (n = 1), spermatocytes (n = 19), spermatids (n = 11), Leydig cells (n = 3), PTM cells (n = 1), and Sertoli cells (n = 4) (Table 1, Figure 1 and Figure 2). The single marker associated with spermatogonia was found in the corresponding cluster (cluster 1). The spermatocyte markers were evenly distributed in all five clusters, but comparing the expression patterns to the profiles identified earlier [10,16] strongly indicated that this cluster (cluster 2) with a reduced expression at pi day 17, mainly contained transcripts from spermatocytes. Most spermatid markers were present in the two clusters that we associated with early and late spermatids (cluster 3 and 4). The transcripts in the somatic cell cluster contained all somatic cell markers (cluster 5), which confirmed that the cluster represented all somatic cells and not only transcripts from Sertoli cells as suggested in our earlier study [10].

Bottom Line: We separated the transcripts into five unique clusters that we associated with spermatogonia, spermatocytes, early spermatids, late spermatids and somatic cells, respectively.We observed large expression changes in the somatic cell profile, which mainly could be attributed to changes in cellularity, but hyperplasia of Leydig cells may also play a role.We speculate that the possible hyperplasia may be caused by lower testosterone production and inadequate inhibin signalling due to missing germ cells.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Background: Radiotherapy is used routinely to treat testicular cancer. Testicular cells vary in radio-sensitivity and the aim of this study was to investigate cellular and molecular changes caused by low dose irradiation of mice testis and to identify transcripts from different cell types in the adult testis.

Methods: Transcriptome profiling was performed on total RNA from testes sampled at various time points (n = 17) after 1 Gy of irradiation. Transcripts displaying large overall expression changes during the time series, but small expression changes between neighbouring time points were selected for further analysis. These transcripts were separated into clusters and their cellular origin was determined. Immunohistochemistry and in silico quantification was further used to study cellular changes post-irradiation (pi).

Results: We identified a subset of transcripts (n = 988) where changes in expression pi can be explained by changes in cellularity. We separated the transcripts into five unique clusters that we associated with spermatogonia, spermatocytes, early spermatids, late spermatids and somatic cells, respectively. Transcripts in the somatic cell cluster showed large changes in expression pi, mainly caused by changes in cellularity. Further investigations revealed that the low dose irradiation seemed to cause Leydig cell hyperplasia, which contributed to the detected expression changes in the somatic cell cluster.

Conclusions: The five clusters represent gene expression in distinct cell types of the adult testis. We observed large expression changes in the somatic cell profile, which mainly could be attributed to changes in cellularity, but hyperplasia of Leydig cells may also play a role. We speculate that the possible hyperplasia may be caused by lower testosterone production and inadequate inhibin signalling due to missing germ cells.

Show MeSH
Related in: MedlinePlus