Team Leader
Staff
- Dr. med. vet. Sarah Gniesmer
- Marion Langeheine, VMTA
Doctoral Students
- Anna Skeries, Veterinarian
- Nanne Fischer, Veterinarian
Research
The research focus of Prof. Brehm's team (Functional Histology and Cell Biology) is in the field of reproductive medicine with a focus on the investigation and characterization of somatic Sertoli cells of the testis.
Current research projects are focusing in particular on direct cell-cell communication via gap junction / connexins (Cx) in the testis and the importance of other junction proteins (like tight and adherens junctions) for spermatogenesis. The use of functional, transgenic animal models with a Sertoli cell- and germ cell-specific deletion of the Connexin43 (Cx43) gene enables comprehensive characterization of the significance of Cx43 for the morphology and function of the testis as well as for the communication between Sertoli, between Sertoli cells cells and germ cells, thus spermatogenesis, and blood testis-barrier function.
To gain more detailed knowledge about the ultrastructural effects of Sertoli cell-specific deletion of Cx43, previous studies analyzed testicular samples by serial block-face scanning electron microscopy (SBF-SEM) and confirmed that Sertoli cell-specific knockout of Cx43 is for example associated with changes in the differentiation state of Sertoli cells. SBF-SEM is also being used in current projects to characterize intratubular cell agglomerates and multilamellar structures in this transgene mouse model.
In addition to the examination of testicular tissue with regard to ultrastructure, the establishment and functional characterization of a primary Sertoli cell culture has already been carried out in order to gain a better understanding of the role of Cx43 in spermatogenesis and the formation of the blood-testis barrier by Sertoli cells in vitro. This in-vitro technique will also be continued in current projects and shall lead to the establishment of an immortalized Sertoli cell line.
Furthermore, in previous studies, the testicular tissue of pubertal mice with Sertoli cell-specific connexin43 knockout was examined with regard to gene expression using next-generation sequencing (NGS). The altered gene expression upon loss of Cx43 indicates that communication between Sertoli cells and germ cells in particular is disrupted
Further investigations for sequencing (single cell RNA sequencing in cooperation with the FLI in Mariensee) of the testicular cell populations involved are planned in current and future projects.
Current projects
Project 1:
Characterization of intratubular cell agglomerates in transgenic mice with a Sertoli cell specific connexin43 knockout (SCCx43KO)
Project 2:
Characterization of multilamellar structures in the seminiferous tubule of wild-type mice and mice with a transgenic Sertoli cell specific connexin43 knockout (SCCx43KO)
Project 3:
Findings in the rete testis and transition region of SCCx43KO mice using immunohistochemistry and electron microscopy
Project 4:
Single-cell RNA sequencing of testes from wild-type and SCCx43KO mice
Project 5:
Characterization of primary Sertoli cell cultures with regard to subsequent immortalization
Range of methods (examples)
Transgenic animal model:
- Sertoli cell-specific deletion of Cx43 (Cre/loxP recombinase system with AMH-Cre and Cx43 floxed mice)
RNA/DNA level:
- PCR
- RT-PCR, RT-PCR after UV-laser assisted microdissection
- Real time-PCR
- DNA genotyping from ear punches (transgenic mouse model)
Protein level:
- Western Blot
- Immunohistology/ immunohistochemistry
- Immunofluorescence
- Immunoelectron microscopy (immunogold method)
Cell and tissue science:
- Light microscopy
- Electron microscopy (TEM, SEM)
- Serial Block-Face Scanning Electron Microscopy (SBF-SEM
Cell culture:
- Primary Sertoli cell culture and cell lines
