Ssue collection was performed between 11:00 AM and 12:00 noon. Two-mm skin punch biopsies were obtained from the volar aspect of the forearm under 1 lidocaine local anesthesia. Specimens were immediately flash-frozen in liquid nitrogen and stored at 280uC.Cell culture and treatmentHuman dermal microvascular endothelial cells (HMVEC) were obtained from Dr. Don Sanger, Beth Israel Deaconess Medical Center, Boston, MA. Human coronary artery endothelial cells (HCAEC) were purchased from Lonza (Basel, Switzerland). Cells were cultured in EGM-2 MV BulletKit Title Loaded From File medium at 37uC in a 10457188 5 CO2 humidified air incubator. Confluent cells at passage 5 to 8 were used in all experiments. One ml of growth medium was added to confluent EC cultures (in 3-cm culture plates) 1 h before IH treatment. Cells (in plates without lids to 16574785 obtain better exposure to gases) were placed in the IH chamber connected to the oxygen controller (Coy Laboratory Products, Inc., Grass Lake, MI, USA), and oxygen cycling was induced through controller-regulated purging of oxygen and nitrogen. Gases were delivered to the IH chamber via water bubblers placed in the tissue culture incubator to maintain adequate temperature (37uC) and humidification. Continuously monitored real-time O2 levels served as input to the controller feedback loop. Cells were exposed to IH for 1 and 2 h, with 9-min cycles comprised of 1.5 min ramp from 20 to 1 oxygen, 3 min 1 oxygen, 1.5 min ramp from 1 to 20 oxygen, and 3 min 20 oxygen.Mouse model of OSAThis study was approved by the Institutional Animal Care and Use Committee at the University of Pittsburgh Medical Center and complied with the American Physiological Society Guidelines for Animal Studies. Male C57BL/6J mice (20?5 g body weight, 9?2 weeks old) were purchased from the Jackson Laboratory (Bar Harbor, ME). Mice were housed in customized cages delivering IH or intermittent room air (IA; control) stimulus, as described [21]. This approach allowed mice to be maintained in their normal environment throughout the protocol. Briefly, a gas control delivery Sense 59TGTGGGAATCCGACGAATG-39 and antisense 59- GTCATATGGTGGAGCTGTGGG-39 for N-Cadherin; sense 59CGGGAATGCAGTTGAGGATC-39 and system regulated the flow of room air, N2, and O2 into the customized cages housing the mice. A series of programmable solenoids and flow regulators enabled inspired O2 to be varied from 20.9 to 5.0?.0 over a 30-s period, followed by a rapid, 30-s reoxygenation to room air levels, using a burst of 100 O2. Hypoxic events occurred at a rate of one event per minute throughout the 12-h light period (8 AM ?8 PM). During the 12-h dark period (8 PM ?8 AM), mice were maintained in constant undisturbed room air environment. Control mice (sham exposure) were exposed to the same gas flow as IH animals, but only room air was used. Mice were exposed to 28 consecutive days of IH or IA, and then anesthetized and their aortas removed and snap frozen in liquid nitrogen.Quantitative reverse transcriptase PCR (qRT-PCR)Total mRNA was isolated from pulverized skin biopsies or mouse aortas, using Trizol reagent (Sigma), according to the manufacturer’s protocol. Total RNA from HMVEC and HCAEC was isolated using RNeasy mini kit from Qiagen (Valencia, CA, USA). cDNA was synthesized using iScript cDNA synthesis kit (Bio-Rad, Hercules, CA, USA) immediately after RNA isolation (to avoid storage-related degradation of RNA samples). Equal amounts of cDNA, an equivalent of 2.5 ng (skin biopsies and mouse aortas) or 5 ng (HCAEC and HMVEC) of RNA, were used in each reaction carried out in iTaq Fast SYBR Green Supermix with ROX (.Ssue collection was performed between 11:00 AM and 12:00 noon. Two-mm skin punch biopsies were obtained from the volar aspect of the forearm under 1 lidocaine local anesthesia. Specimens were immediately flash-frozen in liquid nitrogen and stored at 280uC.Cell culture and treatmentHuman dermal microvascular endothelial cells (HMVEC) were obtained from Dr. Don Sanger, Beth Israel Deaconess Medical Center, Boston, MA. Human coronary artery endothelial cells (HCAEC) were purchased from Lonza (Basel, Switzerland). Cells were cultured in EGM-2 MV BulletKit medium at 37uC in a 10457188 5 CO2 humidified air incubator. Confluent cells at passage 5 to 8 were used in all experiments. One ml of growth medium was added to confluent EC cultures (in 3-cm culture plates) 1 h before IH treatment. Cells (in plates without lids to 16574785 obtain better exposure to gases) were placed in the IH chamber connected to the oxygen controller (Coy Laboratory Products, Inc., Grass Lake, MI, USA), and oxygen cycling was induced through controller-regulated purging of oxygen and nitrogen. Gases were delivered to the IH chamber via water bubblers placed in the tissue culture incubator to maintain adequate temperature (37uC) and humidification. Continuously monitored real-time O2 levels served as input to the controller feedback loop. Cells were exposed to IH for 1 and 2 h, with 9-min cycles comprised of 1.5 min ramp from 20 to 1 oxygen, 3 min 1 oxygen, 1.5 min ramp from 1 to 20 oxygen, and 3 min 20 oxygen.Mouse model of OSAThis study was approved by the Institutional Animal Care and Use Committee at the University of Pittsburgh Medical Center and complied with the American Physiological Society Guidelines for Animal Studies. Male C57BL/6J mice (20?5 g body weight, 9?2 weeks old) were purchased from the Jackson Laboratory (Bar Harbor, ME). Mice were housed in customized cages delivering IH or intermittent room air (IA; control) stimulus, as described [21]. This approach allowed mice to be maintained in their normal environment throughout the protocol. Briefly, a gas control delivery system regulated the flow of room air, N2, and O2 into the customized cages housing the mice. A series of programmable solenoids and flow regulators enabled inspired O2 to be varied from 20.9 to 5.0?.0 over a 30-s period, followed by a rapid, 30-s reoxygenation to room air levels, using a burst of 100 O2. Hypoxic events occurred at a rate of one event per minute throughout the 12-h light period (8 AM ?8 PM). During the 12-h dark period (8 PM ?8 AM), mice were maintained in constant undisturbed room air environment. Control mice (sham exposure) were exposed to the same gas flow as IH animals, but only room air was used. Mice were exposed to 28 consecutive days of IH or IA, and then anesthetized and their aortas removed and snap frozen in liquid nitrogen.Quantitative reverse transcriptase PCR (qRT-PCR)Total mRNA was isolated from pulverized skin biopsies or mouse aortas, using Trizol reagent (Sigma), according to the manufacturer’s protocol. Total RNA from HMVEC and HCAEC was isolated using RNeasy mini kit from Qiagen (Valencia, CA, USA). cDNA was synthesized using iScript cDNA synthesis kit (Bio-Rad, Hercules, CA, USA) immediately after RNA isolation (to avoid storage-related degradation of RNA samples). Equal amounts of cDNA, an equivalent of 2.5 ng (skin biopsies and mouse aortas) or 5 ng (HCAEC and HMVEC) of RNA, were used in each reaction carried out in iTaq Fast SYBR Green Supermix with ROX (.