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Information about mechanical strain in the extracellular space is conducted along collagen fibers connected with integrins and then transmitted within cells. An aim of the study is to verify the hypothesis that the stiffness of cardiac human fibroblast substrates exerts a regulatory effect on collagen metabolism via integrin α2β1 and downstream signaling. The experiments were performed on human cardiac fibroblasts cultured on stiff or soft polyacrylamide gels. Extracellular and intracellular collagen content, metalloproteinase-1 (MMP-1), metalloproteinase-9 (MMP-9) and expression of the α1 chain of the procollagen type I gene (Col1A1) were elevated in cultures settled on soft substrate. The substrate stiffness did not modify tissue inhibitors of matrix metalloproteinase capacity (TIMPs 1–4). Integrin α2β1 inhibition (TC-I 15) or α2 subunit silencing resulted in augmentation of collagen content within the culture. Expression of Col1A1 and Col3A1 genes was increased in TC-I 15-treated fibroblasts. Total and phosphorylated levels of both FAK and Src kinases were elevated in fibroblasts cultured on stiff substrate. Inhibition of FAK (FAK kinase inhibitor 14) or Src kinase (AZM 47527) increased collagen content within the culture. The substrate stiffness exerted a regulatory influence on collagen metabolism via integrin α2β1 and its downstream signaling (FAK and Src kinases) in cardiac fibroblasts.

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SummaryThe overproduction of androgens during the course of foliculogenesis may lead to disturbances in ovulationthe main reason for the establishment of the pathological state known as polycystic ovarian syndrome (PCOS). Furthermore, recently attention has been drawn to the involvement of tachykinins such as substance P (SP) in this process. Apart from this, both in animals and women, the above factors may impair oocyte development. Taking into account the aforementioned data we sought to find and compare the response of isolated porcine oocytes to different doses of testosterone (T) and SP with the goal of clarifying their effect on oocyte growth and meiosis progress. In our experimental approach porcine oocytes were exposed to these factors for 4 h, 20 h or 44 h of culture. The obtained results reveal that both T and SP inhibit growth of porcine oocytes, cumulus cell expansion and meiotic resumption in vitro. Our data show that the inhibitory effect of SP on porcine oocytes is far weaker than the impact of T.

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