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Pkd2 affects the architecture of zebrafish left-right organizer

Background

Dorsal anterior clustering (DAC) of motile cilia in the left-right organizer (LRO) is crucial for normal fluid flow dynamics and correct laterality in zebrafish [1]. We directly demonstrated that charon/dand5 transcription is negatively regulated by strong flow in zebrafish LRO [1] which suggests that LRO cells have the ability to sense fluid flow and influence gene expression patterns, but how? Pkd2 ion channel is a good candidate because it participates in a mechanosensory complex that senses fluid flow and induces a calcium inward flux in kidney cells [2] and in nodal cells [3]. In agreement, mouse and zebrafish mutants for Pkd2 have LR defects [4, 5]. However, Pkd2 is also involved in cell polarity during migration [6] and in extracellular matrix deposition [7] implying a role for Pkd2 in cell morphogenesis.

Objective

Determine whether Pkd2 knockdown affects DAC of ciliated LRO cells.

Methods

dnah7 morpholino [1] was injected to generate static cilia without affecting DAC [1]. Each embryo was screened for static cilia by high-speed videomicroscopy. In parallel, Pkd2 knockdowns were imaged for flow dynamics followed by quantification of anterior / posterior cilia number through two-photon microscopy.

Results

Pkd2 knockdown, contrary to Dnah7 knockdown, caused a remodelling in the LRO architecture by disrupting DAC. Moreover, Pkd2 knockdown resulted in abnormal fluid flow as a consequence of defective DAC.

Conclusions

Comparing Dnah7 and Pkd2 knockdowns we concluded that Pkd2 mediated pathway affects LRO morphogenesis by a mechanism that seems to be independent of its role in fluid flow mechanosensation. Meaning that Pkd2 triggers additional responses from those caused by LRO flow.

Supported by FCT-ANR/BEX-BID/0153/2012 grant.

References

  1. 1.

    Sampaio P, Ferreira RR, Guerrero A, Pintado P, Tavares B, Amaro J, et al: Left-Right Organizer Flow Dynamics: How Much Cilia Activity Reliably Yields Laterality?. Developmental Cell. 2014, 29 (6): 716-728. 10.1016/j.devcel.2014.04.030.

  2. 2.

    Nauli SM, Alenghat FJ, Luo W, Williams E, Vassilev P, Li X, et al: Polycystins 1 and 2 mediate mechanosensation in the primary cilium of kidney cells. Nat Genet. 2003, 33 (2): 129-137. 10.1038/ng1076.

  3. 3.

    McGrath J, Somlo S, Makova S, Tian X, Brueckner M: Two Populations of Node Monocilia Initiate Left-Right Asymmetry in the Mouse. Cell. 2003, 114 (1): 61-73. 10.1016/S0092-8674(03)00511-7.

  4. 4.

    Pennekamp P, Karcher C, Fischer A, Schweickert A, Skryabin B, Horst J, et al: The Ion Channel Polycystin-2 Is Required for Left-Right Axis Determination in Mice. Current Biology. 2002, 12 (11): 938-943. 10.1016/S0960-9822(02)00869-2.

  5. 5.

    Schottenfeld J, Sullivan-Brown J, Burdine RD: Zebrafish curly up encodes a Pkd2 ortholog that restricts left-side-specific expression of southpaw. Development. 2007, 134 (8): 1605-1615. 10.1242/dev.02827.

  6. 6.

    Outeda P, Huso DL, Fisher SA, Halushka MK, Kim H, Qian F, et al: Polycystin Signaling Is Required for Directed Endothelial Cell Migration and Lymphatic Development. Cell Reports. 2014, 7 (3): 634-644. 10.1016/j.celrep.2014.03.064.

  7. 7.

    Mangos S, Lam P, Zhao A, Liu Y, Mudumana S, Vasilyev A, et al: The ADPKD genes pkd1a/b and pkd2 regulate extracellular matrix formation. Disease Models & Mechanisms. 2010, 3 (5-6): 354-365. 10.1242/dmm.003194.

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Correspondence to S Lopes.

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Keywords

  • Fluid Flow
  • Flow Dynamic
  • Nodal Cell
  • Morpholino
  • Normal Fluid