Homogenates were suspended in SDS lysis buffer with added protease and phosphatase inhibitors at 4 C. capable of inducing angiogenesis both in vitro and in vivo, using human umbilical vein endothelial cells (HUVEC) and chicken chorioallantoic membrane (CAM), respectively. In addition, we investigated if the RhoA/ROCK pathway is responsible for the integration of Netrin signaling to control vessel formation. Results The paracrine angiogenic effect of the WJ-MSC-conditioned media is mediated at least in part by Netrin-1 given that pharmacological blockage of Netrin-1 in WJ-MSC resulted Amfenac Sodium Monohydrate in diminished angiogenesis on HUVEC. When HUVEC were stimulated with exogenous Netrin-1 assayed at physiological concentrations (10C200 ng/mL), endothelial vascular migration occurred in a concentration-dependent manner. In line with our determination of Netrin-1 present in WJ-MSC-conditioned media we were able to obtain endothelial Amfenac Sodium Monohydrate tubule formation even in the pg/mL range. Through CAM assays we validated that WJ-MSC-secreted Netrin-1 promotes an increased angiogenesis in vivo. Netrin-1, secreted by WJ-MSC, might mediate its angiogenic effect through specific cell surface receptors on the endothelium, such as UNC5b and/or integrin 61, expressed in HUVEC. However, the angiogenic response of Netrin-1 seems not to be mediated through the RhoA/ROCK pathway. Conclusions Thus, here we show that stromal production of Netrin-1 is a critical component of the vascular regulatory machinery. This signaling event may have deep implications in the modulation of several processes related to a number of diseases where angiogenesis plays a key role in vascular homeostasis. Electronic supplementary material The online version of this article (doi:10.1186/s13287-017-0494-5) contains supplementary material, which is available to authorized users. nor a family history of premature vascular diseases, and no regular consumption of medication. Written consent from these patients was obtained. The ethics committee of the University of Chile and Dr. Luis Tisn Brousse Hospital approved this protocol. Within 24 h umbilical cords were processed in our laboratory following standard procedures [19, 25]. Briefly, the umbilical cord was dissected to discard blood vessels, then was cut into 2-mm2 pieces and digested with collagenase I (1 g/L, Gibco by Life Technologies, Carlsbad, CA, USA) in phosphate-buffered saline (PBS, pH 7.4) with gentle agitation at 37 C for 16 h in order to disaggregate the tissue. The cells obtained by subsequent centrifugation (2000 rpm, 10 min) were then washed and seeded in Dulbeccos modified Eagles medium (DMEM) (Life Technologies) containing 10% fetal bovine serum (FBS) (Hyclone, Logan, UT, USA) with antibiotics (100 U/mL penicillin/streptomycin, Thermo Fisher Scientific, Waltham, |MA, USA) and maintained in this condition for 24 h at 37 C, 5% CO2. Afterwards, non-adherent cells were discarded and adherent cells were incubated at 37 C, 5% CO2, changing the medium every 2C3 days. All primary cultures of WJ-MSC were used between passages 2C5. Human adipose tissue-derived mesenchymal stem cells (AD-MSC) and human bone marrow-derived mesenchymal stem cells (BM-MSC), kindly donated by Dr. Montencinos, were cultivated in the same conditions as WJ-MSC. Human umbilical vein endothelial cells (HUVEC) isolation and culture Rabbit Polyclonal to OR4F4 HUVEC were obtained from full-term normal umbilical cords as described [26]. Briefly, umbilical veins were rinsed with warm (37 C) phosphate-buffered saline solution Amfenac Sodium Monohydrate (PBS, in mM: NaCl 136, KCl 2.7, Na2HPO4 7.8, KH2PO4 1.5, pH 7.4) and endothelial cells were isolated by collagenase (0.2 mg/mL) digestion and cultured (37 C, 5% CO2) up to passage 2 in medium 199 (M199) supplemented with 10% newborn calf serum, 10% fetal calf serum, 3.2 mM L-glutamine and 100 U/mL penicillin-streptomycin. The medium was changed every 2 days until confluence was reached. All primary cultures of HUVEC were used between passages 2C5. Conditioned media precipitation and Netrin-1 determination In order to evaluate the secretion of Netrins by WJ-MSC, conditioned media were collected after 48 h of culture in serum starvation. To analyze the samples, through Western blotting, we concentrated the proteins secreted by the cultured cells. Briefly, conditioned media was distributed in aliquots of 1 1 mL. Next, 500 L of methanol at ?20 C was added and vortexed for 30 s, then 125 L of chloroform was added following a final vortex step of 20 s, medium was centrifuged at 14,000 rpm for 5 min. Finally, the interface was recovered, and suspended in.