Deletion of newly described pro-survival molecule Pellino-1 increases oxidative stress, downregulates cIAP2/NF-κB cell survival pathway, reduces angiogenic response, and thereby aggravates tissue function in mouse ischemic models.

INTRODUCTION: In the present study, we aimed to explore the functional role of Pellino-1 (Peli1) in inducing neovascularization after myocardial infarction (MI) and hindlimb ischemia (HLI) using Peli1 global knockout mice (Peli1-/-). Recently we have shown that Peli1, an E3 ubiquitin ligase, induce angiogenesis and improve survivability, with decreased necrosis of ischemic skin flaps. METHODS: Peli1fl/fl and Peli1-/- mice were subjected to either permanent ligation of the left anterior descending coronary artery (LAD) or sham surgery (S). Tissues from the left ventricular risk area were collected at different time points post-MI. In addition, Peli1fl/fl and Peli1-/- mice were also subjected to permanent ligation of the right femoral artery followed by motor function scores, Doppler analysis for blood perfusion and immunohistochemical analysis. RESULTS: Global Peli1 knockout exacerbated myocardial dysfunction, 30 and 60 days after MI compared to wild type (WT) mice as measured by echocardiogram. In addition, Peli1-/- mice also showed decreased motor function scores and perfusion ratios compared with Peli1fl/fl mice 28 days after the induction of HLI. The use of Peli1 in adenoviral gene therapy following HLI in CD1 mice improved the perfusion ratio at 28 days compared to Ad.LacZ-injected mice. CONCLUSION: These results suggest new insights into the protective role of Peli1 on ischemic tissues and its influence on survival signaling.

An Alternative Approach to Carotid Endarterectomy in the High Carotid Bifurcation.

BACKGROUND: Surgical exposure of a high carotid bifurcation (HCB) for carotid endarterectomy (CEA) can be technically challenging due to the presence of bony structures in the most cranial portion of the neck and is associated with significant morbidity making carotid artery stenting (CAS) a common alternative. However, a high transverse neck incision with subplatysmal flaps facilitates CEA in these patients without additional exposure techniques. We present a high transverse neck incision with subplatysmal flaps as an alternative to the standard surgical exposure of the carotid bifurcation to facilitate CEA in patients with HCB. METHODS: Four patients with carotid bifurcations located cranial to the C3-4 vertebral interspace (identified on preoperative imaging) requiring intervention underwent CEA using a high transverse neck incision through an existing skin crease with subplatysmal flap elevation. CEA was performed in a standard fashion with bovine pericardial patch. RESULTS: Two male and 2 female patients with an average age of 65 years successfully underwent CEA using this incision. One patient underwent concurrent carotid body tumor excision. None of the patients required mandibulotomy or hyoid bone resection. Two patients required division of the posterior belly of the digastric muscle. There were no perioperative complications. Primary patency was 100% in the 4 patients with surveillance studies, and mean follow-up of 160 days (range 54-369 days). There were no significant cranial nerve injuries. No patient required conversion to an endovascular procedure due to inaccessibility of the lesion or subsequent interventions for incomplete endarterectomy. CONCLUSIONS: A high transverse incision with subplatysmal flaps is a safe, effective, and cosmetically preferable surgical approach in patients with HCB requiring carotid artery intervention and may be an alternative to CAS.

Disruption of VEGF Mediated Flk-1 Signaling Leads to a Gradual Loss of Vessel Health and Cardiac Function During Myocardial Infarction: Potential Therapy With Pellino-1.

Background The present study demonstrates that the ubiquitin E3 ligase, Pellino-1 (Peli1), is an important angiogenic molecule under the control of vascular endothelial growth factor (VEGF) receptor 2/Flk-1. We have previously reported increased survivability of ischemic skin flap tissue by adenovirus carrying Peli1 (Ad-Peli1) gene therapy in Flk-1+/- mice. Methods and Results Two separate experimental groups of mice were subjected to myocardial infarction ( MI ) followed by the immediate intramyocardial injection of adenovirus carrying LacZ (Ad-LacZ) (1×109 pfu) or Ad-Peli1 (1×109 pfu). Heart tissues were collected for analyses. Compared with wild-type ( WTMI ) mice, analysis revealed decreased expressions of Peli1, phosphorylated (p-)Flk-1, p-Akt, p- eNOS , p- MK 2, p-IκBα, and NF -κB and decreased vessel densities in Flk-1+/- mice subjected to MI (Flk-1+/- MI ). Mice ( CD 1) treated with Ad-Peli1 after the induction of MI showed increased ß-catenin translocation to the nucleus, connexin 43 expression, and phosphorylation of Akt, eNOS , MK 2, and IκBα, that was followed by increased vessel densities compared with the Ad-LacZ-treated group. Echocardiography conducted 30 days after surgery showed decreased function in the Flk1+/- MI group compared with WTMI , which was restored by Ad-Peli1 gene therapy. In addition, therapy with Ad-Peli1 stimulated angiogenic and arteriogenic responses in both CD 1 and Flk-1+/- mice following MI . Ad-Peli1 treatment attenuated cardiac fibrosis in Flk-1+/- MI mice. Similar positive results were observed in CD 1 mice subjected to MI after Ad-Peli1 therapy. Conclusion Our results show for the first time that Peli1 plays a unique role in salvaging impaired collateral blood vessel formation, diminishes fibrosis, and improves myocardial function, thereby offering clinical potential for therapies in humans to mend a damaged heart following MI .

Increased survivability of ischemic skin flap tissue in Flk-1+/- mice by Pellino-1 intervention.

OBJECTIVE: Reduced skin flap survival due to ischemia is a serious concern during reconstructive cosmetic surgery. The absence of VEGF and its receptors during ischemia may lead to flap failure. We identified Peli1, a 46-kDa protein, as a proangiogenic molecule and is directly regulated by VEGF. Therefore, we hypothesized that Peli1 acts downstream of Flk-1/VEGFR2 and aids in skin flap survival during ischemia. METHODS: Scratch and matrigel assays were performed to observe cell proliferation, migration, and tube formation in vitro. Western blot analysis was carried out to detect the phosphorylation of Akt (p-Akt) and MAPKAPK2 (p-MK2) in HUVECs. The translational potential of Peli1 pretreatment in the rescue of skin flap tissue was studied in vivo using Flk-1+/- mice. Animals underwent dorsal ischemic skin flap surgery, and the tissue was collected on day 12 for analysis. RESULTS: Western blot analysis revealed a direct relationship between Peli1 and VEGF, as demonstrated by loss-of-function and gain-of-function studies. In addition, pretreatment with Ad.Peli1 restored the phosphorylation of Akt and MK2 and improved the migration potential of Flk-1-knockdown cells. Ad.Peli1 pretreatment salvaged the ischemic skin flap of Flk-1+/- mice by increasing blood perfusion and reducing the inflammatory response and the extent of necrosis. CONCLUSION: Our findings reveal that Peli1 is a proangiogenic molecule that acts downstream of VEGF-Flk-1 and restores angiogenesis and enhances skin flap survivability.