The behavior of cells is governed by signals originating from their local environment, including mechanical forces exerted on the cells. Forces are transduced by mechanosensitive proteins, which can impinge on signaling cascades that are also activated by growth factors. We investigated the cross-talk between mechanical and biochemical signals in the regulation of intracellular signaling networks in epithelial monolayers. Phosphoproteomic and transcriptomic analyses on epithelial monolayers subjected to mechanical strain revealed the activation of extracellular signal–regulated kinase (ERK) downstream of the epidermal growth factor receptor (EGFR) as a predominant strain-induced signaling event. Strain-induced EGFR-ERK signaling depended on mechanosensitive E-cadherin adhesions. Proximity labeling showed that the metalloproteinase ADAM17, an enzyme that mediates shedding of soluble EGFR ligands, was closely associated with E-cadherin. A probe that we developed to monitor ADAM-mediated shedding demonstrated that mechanical strain induced ADAM activation. Mechanically induced ADAM activation was essential for mechanosensitive, E-cadherin–dependent EGFR-ERK signaling. Together, our data demonstrate that mechanical strain transduced by E-cadherin adhesion triggers the shedding of EGFR ligands that stimulate downstream ERK activity. Our findings illustrate how mechanical signals and biochemical ligands can operate within a linear signaling cascade.

Background: Diabetes mellitus (DM) is a common potentially life-threatening endocrine disorder in pets and humans. Since only symptomatic treatment is available, a more sustainable treatment is urgently needed. Objective: The aim of this study is to establish functional differentiated canine pancreatic β-cells that release insulin upon glucose stimulus. Methods: Pancreatic tissue was obtained from surplus material of healthy dogs (n = 4), euthanized for non-pancreatic related research. Ductal cells were isolated and expanded in dog pancreas expansion media (dpEM) and differentiated and maturated in five sequentially added pancreas differentiation media (PDMs). Gene expression was analyzed by reversed transcriptase qPCR (RT-qPCR), and insulin release was analyzed with a canine-specific ELISA. Results: Canine pancreatic ductal cells (LGR5 and SOX9 expression) were differentiated into β-cells expressing key β-cell-related genes: Pancreatic and duodenal homeobox 1 (PDX1), NK6 Homeobox 1 (NKX6.1), Glucose Transporter Type 2 (GLUT2), Proprotein convertase subtilisin/kexin type 1 (PCSK1), and low levels of insulin. Neither Glucagon (α-cells) nor LGR5 and SOX9 were expressed, and somatostatin was expressed at low levels. The differentiated cells released insulin upon glucose stimulation. Conclusion and implications: The step-by-step differentiation protocol, mimicking pancreatic organogenesis, resulted in β-cells secreting insulin levels suitable for β-cell disease modelling. It remains to be seen if stem cells from diseased animals behave similarly.