preparation-murine-submandibular-salivary-gland-for-upright

Preparation of Murine Submandibular Salivary Gland for Upright Intravital Microscopy

The submandibular salivary gland (SMG) is one of the three major salivary glands, and is of interest for many different fields of biological research, ...

University of Bern

The serine and threonine kinase MST1 is the mammalian homolog of Hippo. MST1 is a critical mediator of the migration, adhesion, and survival of T cells; however, these functions of MST1 are independent of signaling by its typical effectors, the kinase LATS and the transcriptional coactivator YAP. The kinase NDR1, a member of the same family of kinases as LATS, functions as a tumor suppressor by preventing T cell lymphomagenesis, which suggests that it may play a role in T cell homeostasis. We generated and characterized mice with a T cell-specific double knockout of Ndr1 and Ndr2 (Ndr DKO). Compared with control mice, Ndr DKO mice exhibited a substantial reduction in the number of naïve T cells in their secondary lymphoid organs. Mature single-positive thymocytes accumulated in the thymus in Ndr DKO mice. We also found that NDRs acted downstream of MST1 to mediate the egress of mature thymocytes from the thymus, as well as the interstitial migration of naïve T cells within popliteal lymph nodes. Together, our findings indicate that the kinases NDR1 and NDR2 function as downstream effectors of MST1 to mediate thymocyte egress and T cell migration. 

The kinases NDR1/2 act downstream of the Hippo homolog MST1 to mediate both egress of thymocytes from the thymus and lymphocyte motility.

Parenchymal migration of naive CD4 T cells in lymph nodes (LNs) is mediated by the Rac activator DOCK2 and PI3Kγ and is widely assumed to facilitate efficient screening of dendritic cells (DCs) presenting peptide-MHCs (pMHCs). Yet how CD4 T cell motility, DC density, and pMHC levels interdependently regulate such interactions has not been comprehensively examined. Using intravital imaging of reactive LNs in DC-immunized mice, we show that pMHC levels determined the occurrence and timing of stable CD4 T cell-DC interactions. Despite the variability in interaction parameters, ensuing CD4 T cell proliferation was comparable over a wide range of pMHC levels. Unexpectedly, decreased intrinsic motility of DOCK2 CD4 T cells did not impair encounters with DCs in dense paracortical networks and, instead, increased interaction stability, whereas PI3Kγ deficiency had no effect on interaction parameters. In contrast, intravital and whole-organ imaging showed that DOCK2-driven T cell motility was required to detach from pMHC DCs and to find rare pMHC DCs. In sum, our data uncover flexible signal integration by scanning CD4 T cells, suggesting a search strategy evolved to detect low-frequency DCs presenting high cognate pMHC levels.

Xenia Ficht

Theodor-Kocher Institute

University of Bern

Preparation of Murine Submandibular Salivary Gland for Upright Intravital Microscopy

Xenia Ficht

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Theodor-Kocher Institute

University of Bern

Preparation of Murine Submandibular Salivary Gland for Upright Intravital Microscopy

Theodor-Kocher Institute