Biology subjects

Stumpp, T.

Publications and source records attributed to Stumpp, T..

3 recordsLinked to original sources

bioRxiv2026

A scalable mesh microelectrode array platform for longitudinal electrophysiology in neural spheroids

Electrophysiological interfacing remains difficult in three-dimensional in vitro models, when using planar microelectrode arrays or optical methods. This challenge limits experimental progress using such models, despite their promise of better physiological relevance than monolayer cell culture. Mesh MEAs which can integrate conformally on or even within tissue offer a possible solution but are not yet widely accessible. Here, we present a mesh MEA device, designed as a simple, manufacturable platform for spheroid electrophysiology. In neural spheroids, the device enabled longitudinal electrophysiological recordings and pharmacological modulation of spontaneous electrical activity. On native polyimide meshes, spheroids maintained their shape while cells enveloped the mesh, embedding electrodes to a depth of 100 {micro}m after 2 weeks. In contrast, laminin biofunctionalization of the mesh promoted outgrowth and migration of cells. This device and associated methods should be adaptable to organoids, ex vivo tissue, or bioengineered in vitro models.

neuroscience↗

bioRxiv2020

Non-apoptotic Role of Cleaved Caspase-3 in Rat Male Germ Cell Development

Germ cells emerge from the epiblast and migrate to the gonads, where they become gonocytes. The gonocytes are the precursors of the spermatogonial stem cells, but little is known about their differentiation. The rigid control of gonocyte proliferation, quiescence and pluripotency marker expression is crucial for spermatogonia development. We have previously suggested that cleaved caspase-3 (Casp3) might play a non-apoptotic role in gonocyte quiescence. Here we describe when rat fetal gonocyte enter mitotic arrest and show that Casp3 inhibition in these cells affects the expression of cell cycle genes. The expression of Ki67, p27Kip, Retinoblastoma 1 (pRb1), NANOG and CASP3 was investigated in 15, 17 and 19 days post coitum rat embryo gonads. The results show that Ki67 and pRB1 proteins are downregulated from 15 days post coitum to 19 days post coitum, whereas p27Kip, NANOG and CASP3 are upregulated. This suggests that rat germ cells start to enter quiescence around 15dpc and that CASP3 and NANOG seem to play a role in this process. CASP3 labelling formed a ring in gonocyte cytoplasm, which is clearly distinct from apoptotic cell labelling, and coincided with NANOG labelling. CASP3 inhibition lead to an increase of Pcna expression and to a decrease of p27kip and p21cip expression. These results suggest that cleaved CASP3 has a role in rat male germ cell development which can be related to the control of the cell cycle genes.

developmental biology↗

bioRxiv2019

Dynamics of Sox2 expression during rat germ cell development and its relationship with emergence of spermatogonia

1.The gonocytes represent a specific phase of male gem cell development that precedes spermatogonial stem cell differentiation. Here, we describe the expression of Sox2, an OCT4 partner, during rat germ cell development. Our hypothesis is that SOX2 has a cytoplasmic role during gonocyte-to-spermatogonia transition. Male rat embryos and testes were submitted to the analysis of Sox2 expression. Sox2 was detected in germ cells from 14 days post-conception (dpc) to 8dpp. SOX2 was present in 14dpc and 15dpc embryos and absent at 17 and 19dpc; however, it did not show direct correlation with mRNA. SOX2 labelling was detected after birth and its expression increased from 1dpp to 5dpp. SOX2 was localized in the cytoplasm and showed a granulated pattern similar to P-bodies. Indeed, GW182/SOX2 and LIN28/SOX2 double-labelling showed that SOX2 partially co-localized with the P-bodies components GW182 and LIN28. At 8dpp SOX2 was detected in the nucleus and/or in the cytoplasm of spermatogonia, whereas at 25dpp it was detected in the nucleus of rare spermatogonia. This suggests that SOX2 localization changes during gonocytes to spermatogonia transition.

developmental biology↗