Specific heparan sulfate structures modulate FGF10-mediated submandibular gland epithelial morphogenesis and differentiation.
FGF10, a heparan sulfate (HS)-binding growth factor, is required for branching morphogenesis of mouse submandibular glands (SMGs). HS increases the affinity of FGF10 for FGFR2b, which forms an FGF10.FGFR2b.HS ternary signaling complex, and results in diverse biological outcomes, including proliferation and epithelial morphogenesis. Defining the HS structures involved in specific FGF10-mediated events is critical to understand how HS modulates growth factor signaling in specific developmental contexts. We used HS-deficient BaF3/FGFR2b cells, which require exogenous HS to proliferate, to investigate the HS requirements for FGF10-mediated proliferation and primary SMG epithelia to investigate the structural requirements of HS for FGF10-mediated epithelial morphogenesis. In BaF3/FGFR2b cells, heparin with at least 10 saccharides and 6-O-, 2-O-, and N-sulfates were required for maximal proliferation. During FGF10-mediated SMG epithelial morphogenesis, HS increased proliferation and end bud expansion. Defined heparin decasaccharide libraries showed that 2-O-sulfation with either an N-or 6-O-sulfate induced end bud expansion, whereas decasaccharides with 6-O-sulfation alone induced duct elongation. End bud expansion resulted from increased FGFR1b signaling, with increased FGFR1b, Fgf1, and Spry1 as well as increased Aqp5 expression, a marker of end bud differentiation. Duct elongation was associated with expression of Cp2L1, a marker of developing ducts. Collectively, these findings show that the size and sulfate patterns of HS modulate specific FGF10-mediated events, such as proliferation, duct elongation, end bud expansion, and differentiation, and provide mechanistic insight as to how the developmental localization of specific HS structures in tissues influences FGF10-mediated morphogenesis and differentiation.
Patel
Vaishali N
VN
Matrix and Morphogenesis Unit, Laboratory of Cell and Developmental Biology, National Institute of Dental and Craniofacial Research, National Institutes of Health/DHHS, 30 Convent Drive, Bethesda, MD 20892, USA.
Likar
Karen M
KM
Zisman-Rozen
Simona
S
Cowherd
Samuel N
SN
Lassiter
Keyonica S
KS
Sher
Ifat
I
Yates
Edwin A
EA
Turnbull
Jeremy E
JE
Ron
Dina
D
Hoffman
Matthew P
MP
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D051402:Aquaporin 5 / Q000096:biosynthesis; D002454:Cell Differentiation / Q000187:drug effects* / Q000502:physiology; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D004848:Epithelium / Q000196:embryology*; D016220:Fibroblast Growth Factor 1 / Q000096:biosynthesis; D051526:Fibroblast Growth Factor 10 / Q000378:metabolism / Q000494:pharmacology*; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects* / Q000502:physiology; D006497:Heparan Sulfate / Q000378:metabolism*; D006801:Humans; D008565:Membrane Proteins / Q000096:biosynthesis; D051379:Mice; D008813:Mice, Inbred ICR; D009024:Morphogenesis / Q000187:drug effects* / Q000502:physiology; D046912:Multiprotein Complexes / Q000378:metabolism; D009844:Oligosaccharides / Q000378:metabolism; D010750:Phosphoproteins / Q000096:biosynthesis; D051496:Receptor, Fibroblast Growth Factor, Type 1 / Q000096:biosynthesis; D051497:Receptor, Fibroblast Growth Factor, Type 2 / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013363:Submandibular Gland / Q000196:embryology*
D048868:Adaptor Proteins, Signal Transducing; D051402:Aquaporin 5; D016220:Fibroblast Growth Factor 1; D051526:Fibroblast Growth Factor 10; D006497:Heparan Sulfate; D008565:Membrane Proteins; D046912:Multiprotein Complexes; D009844:Oligosaccharides; D010750:Phosphoproteins; D051496:Receptor, Fibroblast Growth Factor, Type 1; D051497:Receptor, Fibroblast Growth Factor, Type 2; C496038:Aqp5 protein, mouse; C496463:FGF10 protein, human; C496464:Fgf10 protein, mouse; C425468:Spry1 protein, mouse; C496349:Fgfr1 protein, mouse; C496354:Fgfr2 protein, mouse