Placental Trophoblast Cell Isolation from the Term Placenta.

Multiple cell lines have been utilized over time in studying placental biology. Still, most of them rely on choriocarcinoma cells or immortalized trophoblast cells that may not be entirely comparable with actual human placental trophoblast cells. Term placentas can be a source of primary villous trophoblasts. However, challenges remain in isolating them and maintaining them in extended culture. This manuscript describes our three-phase protocol utilizing enzymatic/mechanical digestion, modified Percoll gradient density separation, and immunopurification using magnetic beads. The resulting trophoblast culture remains viable for an extended period and highly pure after initial passaging.

JSAP1 and JLP are required for ARF6 localization to the midbody in cytokinesis.

The ADP-ribosylation factor 6 (ARF6) GTPase is important in cytokinesis and localizes to the midbody. However, the mechanism and regulation of ARF6's recruitment to the midbody are largely unknown. Here, we investigated the functions of two binding partners of active ARF6, c-Jun NH2 -terminal kinase (JNK)/stress-activated protein kinase-associated protein 1 (JSAP1) and JNK-associated leucine zipper protein (JLP), by gene knockout and rescue experiments in mouse embryonic fibroblasts. Depleting both JSAP1 and JLP impaired ARF6's localization to the midbody and delayed cytokinesis. These defects were almost completely rescued by wild-type JSAP1 or JLP, but not by JSAP1 or JLP mutants that were unable to interact with active ARF6 or with the kinesin heavy chain (KHC) of kinesin-1. In transfected cells, a constitutively active form of ARF6 associated with KHC only when co-expressed with wild-type JSAP1 or JLP and not with a JSAP1 or JLP mutant. These findings suggest that JSAP1 and JLP, which might be paralogous to each other, are critical and functionally redundant in cytokinesis and control ARF6 localization to the midbody by forming a tripartite complex of JSAP1/JLP, active ARF6, and kinesin-1.

The scaffold protein JLP plays a key role in regulating ultraviolet B-induced apoptosis in mice.

The ultraviolet B (UVB) component of sunlight can cause severe damage to skin cells and even induce skin cancer. Growing evidence indicates that the UVB-induced signaling network is complex and involves diverse cellular processes. In this study, we investigated the role of c-Jun NH2 -terminal kinase-associated leucine zipper protein (JLP), a scaffold protein for mitogen-activated protein kinase (MAPK) signaling cascades, in UVB-induced apoptosis. We found that UVB-induced skin epidermal apoptosis was prevented in Jlp knockout (KO) as well as in keratinocyte-specific Jlp KO mice. Analysis of the repair of UVB-induced DNA damage over time showed no evidence for the involvement of JLP in this process. In contrast, UVB-stimulated p38 MAPK activation in the skin was impaired in both Jlp KO and keratinocyte-specific Jlp KO mice. Moreover, topical treatment of UVB-irradiated mouse skin with a p38 inhibitor significantly suppressed the epidermal apoptosis in wild-type mice, but not in Jlp KO mice. Our findings suggest that JLP in skin basal keratinocytes plays an important role in UVB-induced apoptosis by modulating p38 MAPK signaling pathways. This is the first study to show a critical role for JLP in an in vivo response to environmental stimulation.