Rhodium-catalyzed homo-coupling reaction of aryl Grignard reagents and its application for the synthesis of an integrin inhibitor.

A novel Rh-catalyzed one-pot homo-coupling reaction of aryl Grignard reagents was achieved. The reaction with bromobenzenes having an electron-donating group or a halogen substituent gave the corresponding homo-coupling products in good yields, although the reaction using heterocyclic or aliphatic bromides scarcely proceeded. A Rh(III)-bis(aryl) complex, which might be formed from RhCl(PPh3)3 and the aryl Grignard reagents, plays an important role in giving the homo-coupling products in this reaction. Furthermore, we applied the reaction to the synthesis of a novel inhibitor for integrins which is critical for several diseases.

[Kaposi sarcoma-a complication of treatment refractory ulcerative colitis]. / Das Kaposi-Sarkom ­ eine Komplikation bei therapierefraktärer Colitis ulcerosa.

We report on the incidental finding of Kaposi sarcoma of the colon in the setting of refractory ulcerative colitis treatment. The patient was under long-term immunosuppression with infliximab, vedolizumab, and prednisolone. Serologic analysis excluded human immunodeficiency virus (HIV) infection.

Does perioperative biological therapy increase 30-day post-operative complication rates in inflammatory bowel disease patients undergoing intra-abdominal surgery? A systematic review.

BACKGROUND: Biopharmaceuticals revolutionised inflammatory bowel disease (IBD) treatment. However, it is postulated they compromise immunity, collagen production and angiogenesis resulting in infective post-operative complications and altered wound/anastomotic healing. Research has failed to agree on risks associated with perioperative biologics therefore it was anticipated that a systematic review may provide a consensus and contribute recommendations for clinical practice. METHODS: A systematic review conducted as per PRISMA guidelines included a methodical search of PubMed, Google Scholar, EMBASE/Ovid and Cochrane Library using MeSH and/or keywords for papers published between 01/01/1998 and 04/02/2019.The population analysed included adult ulcerative colitis, Crohn's disease, Indeterminate Colitis or IBD unclassified patients. The intervention was intra-abdominal surgery in patients treated with biological therapy in the preceding 12 weeks compared to patients who had intra-abdominal surgery without biological therapy within the defined timeframe. The primary outcome was surgical site infection (SSI) with secondary outcomes including wound dehiscence, intra-abdominal sepsis/abscess, systemic infection and anastomotic breakdown within 30 days post-procedure. Papers were evaluated by two independent reviewers and those included were assessed for quality/bias using the Newcastle-Ottowa scale. RESULTS: 2064 UC, Crohn's and IC patients were analysed across 8 included studies. Several studies' multivariate analyses demonstrated corticosteroids to be independent predictors of morbidity. There are no increased complications associated with anti-TNFα exposure while vedolizumab increased SSI and small bowel obstruction. CONCLUSION: Prospective studies and randomised control trials are required to clarify study outcomes and recommendations published to date. Presently, biologics should continue to be used and considered beneficial in this population.

Copper-mediated radioiodination reaction through aryl boronic acid or ester precursor and its application to direct radiolabeling of a cyclic peptide.

A copper-mediated radioiodination using aryl boronic precursors is attracting attention as a solution to oxidative iododestannylation and nickel-mediated radioiodination drawbacks. The copper-mediated radiolabeling method allows radioiodination at room temperature with stable aryl boronic precursors without preparing complex starting materials or reagents and can be performed in a reaction vessel exposed to air. This method has good potential in radiochemistry; however, studies on the scope of copper-mediated radioiodination through boronic precursors are insufficient. In particular, few reports have demonstrated the effect of protecting groups on radiolabeling efficiency. Therefore, the effect of the protecting group of aryl boronic acids on the copper-mediated radioiodination was investigated. In addition, this method, which does not require heating, is expected to be useful for direct radiolabeling of peptides. Thus, we attempted direct radioiodination of c(RGDyk) as an example. The resulting radioiodination method was well tolerated in various substrates and was unaffected by the pinacol ester-type protecting group. Also, c(RGDyk) was labeled with 125 I via copper-mediated radioiodination using an aryl boronic acid precursor. The reaction time and yield were improved, compared with the indirect method. Furthermore, the large difference in polarity between the boronic acid precursor and the radiolabeled compound facilitated purification.

No Benefit of Concomitant Immunomodulator Therapy on Efficacy of Biologics That Are Not Tumor Necrosis Factor Antagonists in Patients With Inflammatory Bowel Diseases: A Meta-analysis.

BACKGROUND & AIMS: There is debate over whether patients with inflammatory bowel diseases (IBD) treated with biologics that are not tumor necrosis factor antagonists (such as vedolizumab or ustekinumab) should receive concomitant treatment with immunomodulators. We conducted a meta-analysis to compare the efficacy and safety of concomitant immunomodulator therapy vs vedolizumab or ustekinumab monotherapy. METHODS: In a systematic search of publications, through July 31, 2019, we identified 33 studies (6 randomized controlled trials and 27 cohort studies) of patients with IBD treated with vedolizumab or ustekinumab. The primary outcome was clinical benefit, including clinical remission, clinical response, or physician global assessment in patients who did vs did not receive combination therapy with an immunomodulator. Secondary outcomes were endoscopic improvement and safety. We performed random-effects meta-analysis and estimated odds ratio (OR) and 95% CIs. RESULTS: Overall, combination therapy was not associated with better clinical outcomes in patients receiving vedolizumab (16 studies: OR, 0.84; 95% CI, 0.68-1.05; I2=13.9%; Q test P = .17) or ustekinumab (15 studies: OR, 1.1; 95% CI, 0.87-1.38; I2 = 11%; Q test P = .28). Results were consistent in subgroup analyses, with no difference in clinical remission or response in induction vs maintenance studies or in patients with Crohn's disease vs ulcerative colitis in studies of vedolizumab. Combination therapy was not associated with better endoscopic outcomes in patients receiving vedolizumab (3 studies: OR, 1.13; 95% CI, 0.48-2.68; I2 = 0; Q test P=.96) or ustekinumab (2 studies: OR, 0.58; 95% CI, 0.21-1.16; I2 = 47%; Q test P = .17). Combination therapy was not associated with an increase in adverse events during vedolizumab therapy (4 studies: OR, 1.17; 95% CI, 0.75-1.84; I2 = 0; Q test P = .110). CONCLUSIONS: In a meta-analysis of data from studies of patients with IBD, we found that combining vedolizumab or ustekinumab with an immunomodulator is no more effective than monotherapy in induction or maintenance of remission.

Dual antagonists of α5ß1/αvß1 integrin for airway hyperresponsiveness.

Inhibition of integrin α5ß1 emerges as a novel therapeutic option to block transmission of contractile forces during asthma attack. We designed and synthesized novel inhibitors of integrin α5ß1 by backbone replacement of known αvß1 integrin inhibitors. These integrin α5ß1 inhibitors also retain the nanomolar potency against αvß1 integrin, which shows promise for developing dual integrin α5ß1/αvß1 inhibitor. Introduction of hydrophobic adamantane group significantly boosted the potency as well as selectivity over integrin αvß3. We also demonstrated one of the inhibitors (11) reduced airway hyperresponsiveness in ex vivo mouse tracheal ring assay. Results from this study will help guide further development of integrin α5ß1 inhibitors as potential novel asthma therapeutics.

Risuteganib-a novel integrin inhibitor for the treatment of non-exudative (dry) age-related macular degeneration and diabetic macular edema.

INTRODUCTION: Non-exudative (dry) age-related macular degeneration (AMD) and diabetic macular edema (DME) are leading causes of vision loss worldwide. Besides age-related eye disease study (AREDS) vitamin supplements, there are no efficacious pharmaceutical interventions for dry AMD available. While numerous pharmacologics are available to treat diabetic macular edema (DME), many patients respond suboptimally to existing therapies. Risuteganib is a novel anti-integrin peptide that targets the multiple integrin heterodimers involved in the pathophysiology of dry AMD and DME. Inhibiting these selected integrin heterodimers may benefit patients with these conditions. AREAS COVERED: This article offers a brief overview of current pharmaceuticals available for dry AMD and DME. The proposed role of integrins in AMD and DME is reviewed and later, risuteganib, a novel anti-integrin peptide is introduced. The data from initial Phase 1 and Phase 2 risuteganib clinical trials are discussed in the latter part of the paper. EXPERT OPINION: While there are currently limited treatment options for dry AMD, more data are needed before we can truly evaluate the benefits of adopting risuteganib into the clinic. Conversely, several effective treatment options exist for DME; hence, risuteganib must show that it can add to these results, especially in those with refractory disease, before retina specialists adopt risuteganib into their treatment regimens.

LXW7 attenuates inflammation via suppressing Akt/nuclear factor kappa B and mitogen-activated protein kinases signaling pathways in lipopolysaccharide-stimulated BV2 microglial cells.

Microglia activation is closely linked to ischemia, various chronic neurodegenerative diseases (e.g., Alzheimer's disease, Parkinson's disease, multiple sclerosis, amyotrophic lateral sclerosis), and many other central nervous system diseases. Accumulating evidence suggests that depressing the microglial inflammatory response could be an effective treatment for inflammatory disorders. The integrin αvß3 inhibitor LXW7 has a neuroprotective effect; however, its anti-inflammatory effects and underlying mechanism remain unclear. Thus, we examined whether LXW7 would inhibit inflammatory cytokines and mediators, and we evaluated the potential mechanisms of its neuroprotective effects. Nitrite analysis revealed LXW7 reduced the nitric oxide (NO) level. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) suggested that LXW7 suppressed the expression of proinflammatory genes for tumor necrosis factor-alpha (TNF-α), interleukin 1-beta (IL-1ß), inducible nitric oxide synthase (iNOS), cyclooxygenase 2 (COX-2), and anti-inflammatory gene interleukin 10 (IL-10) at the messenger ribonucleic acid level. Enzyme-linked immunosorbent assay results demonstrated that LXW7 treatment reduced the expression of prostaglandin E2 (PGE2), TNF-α, IL-1ß and IL-10 at the protein level. Western blotting was conducted to confirm the upregulation of inflammatory factors, including iNOS and COX-2 at the protein level. LXW7 inhibited major genes in the Akt/NF-κB and c-Jun NH2-terminal kinase/ mitogen-activated protein kinases (JNK/MAPK) signaling pathways. Immunofluorescence revealed that LXW7 inhibited the nuclear translocation of nuclear factor kappa B (NF-κB). Thus, LXW7 effectively alleviated LPS-induced inflammatory damage and had neuroprotective effects. The anti-inflammatory effects of LXW7 may be associated with the inhibition of microglial activation via Akt/NF-κB and JNK/MAPK signaling pathways by blocking integrin αvß3 receptor. The present study's findings suggest that LXW7 has a substantial therapeutic potential for treating inflammatory and neurodegenerative diseases.

The functional role of integrins during intra- and extravasation within the metastatic cascade.

Formation of distant metastases is by far the most common cause of cancer-related deaths. The process of metastasis formation is complex, and within this complex process the formation of migratory cells, the so called epithelial mesenchymal transition (EMT), which enables cancer cells to break loose from the primary tumor mass and to enter the bloodstream, is of particular importance. To break loose from the primary cancer, cancer cells have to down-regulate the cell-to-cell adhesion molecuIes (CAMs) which keep them attached to neighboring cancer cells. In contrast to this downregulation of CAMS in the primary tumor, cancer cells up-regulate other types of CAMs, that enable them to attach to the endothelium in the organ of the future metastasis. During EMT, the expression of cell-to-cell and cell-to-matrix adhesion molecules and their down- and upregulation is therefore critical for metastasis formation. Tumor cells mimic leukocytes to enable transmigration of the endothelial barrier at the metastatic site. The attachment of leukocytes/cancer cells to the endothelium are mediated by several CAMs different from those at the site of the primary tumor. These CAMs and their ligands are organized in a sequential row, the leukocyte adhesion cascade. In this adhesion process, integrins and their ligands are centrally involved in the molecular interactions governing the transmigration. This review discusses the integrin expression patterns found on primary tumor cells and studies whether their expression correlates with tumor progression, metastatic capacity and prognosis. Simultaneously, further possible, but so far unclearly characterized, alternative adhesion molecules and/or ligands, will be considered and emerging therapeutic possibilities reviewed.

Enhancing Oral Bioavailability of Cyclic RGD Hexa-peptides by the Lipophilic Prodrug Charge Masking Approach: Redirection of Peptide Intestinal Permeability from a Paracellular to Transcellular Pathway.

Hydrophilic peptides constitute most of the active peptides. They mostly permeate via tight junctions (paracellular pathway) in the intestine. This permeability mechanism restricts the magnitude of their oral absorption and bioavailability. We hypothesized that concealing the hydrophilic residues of the peptide using the lipophilic prodrug charge masking approach (LPCM) can improve the bioavailability of hydrophilic peptides. To test this hypothesis, a cyclic N-methylated hexapeptide containing Arg-Gly-Asp (RGD) and its prodrug derivatives, masking the Arg and Asp charged side chains, were synthesized. The library was evaluated for intestinal permeability in vitro using the Caco-2 model. Further investigation of metabolic stability ex vivo models in rat plasma, brush border membrane vesicles (BBMVs), and isolated CYP3A4 microsomes and pharmacokinetic studies was performed on a selected peptide and its prodrug (peptide 12). The parent drug analogues were found to have a low permeability rate in vitro, corresponding to atenolol, a marker for paracellular permeability. Moreover, palmitoyl carnitine increased the Papp of peptide 12 by 4-fold, indicating paracellular permeability. The Papp of the prodrug derivatives was much higher than that of their parent peptides. For instance, the Papp of the prodrug 12P was 20-fold higher than the Papp of peptide 12 in the apical to basolateral (AB) direction. Whereas the permeability in the opposite direction (BA of the Caco-2 model) was significantly faster than the Papp AB, indicating the involvement of an efflux system. These results were corroborated when verapamil, a P-gp inhibitor, was added to the Caco-2 model and increased the Papp AB of prodrug 12P by 3-fold. The prodrug 12P was stable in the BBMVs environment, yet degraded quickly (less than 5 min) in the plasma into the parent peptide 12. Pharmacokinetic studies in rats showed an increase in the bioavailability of peptide 12 > 70-fold (from 0.58 ± 0.11% to 43.8 ± 14.9%) after applying the LPCM method to peptide 12 and converting it to the prodrug 12P. To conclude, the LPCM approach converted the absorption mechanism of the polar peptides from a paracellular to transcellular pathway that tremendously affects their oral bioavailability. The LPCM method provides a solution for the poor bioavailability of RGD cyclohexapeptides and paves the way for other active hydrophilic and charged peptides with poor oral bioavailability.

Small molecules as therapy for uveitis: a selected perspective of new and developing agents.

INTRODUCTION: Intraocular inflammation (uveitis) remains a significant burden of legal blindness. Because of its immune mediated and chronic recurrent nature, common therapy includes corticosteroids, disease-modifying anti-rheumatic drugs and more recently biologics as immune modulatory agents. The purpose of this article is to identify the role of new treatment approaches focusing on small molecules as therapeutic option in uveitis. Areas covered: A MEDLINE database search was conducted through February 2017 using the terms 'uveitis' and 'small molecule'. To provide ongoing and future perspectives in treatment options, also clinical trials as registered at ClinicalTrials.gov were included. Both, results from experimental as well as clinical research in this field were included. Since this field is rapidly evolving, a selection of promising agents had to be made. Expert opinion: Small molecules may interfere at different steps of the inflammatory cascade and appear as an interesting option in the treatment algorithm of uveitis. Because of their highly targeted molecular effects and their favorable bioavailability with the potential of topical application small molecules hold great promise. Nevertheless, a careful evaluation of these agents has to be made, since current experience is almost exclusively based on experimental uveitis models and few registered trials.

The role of α4 integrin in Theiler's murine encephalomyelitis virus (TMEV)-induced demyelinating disease: an infectious animal model for multiple sclerosis (MS).

Natalizumab, which is an antibody against α4 integrin, has been used for the treatment of multiple sclerosis. In the present study, we investigated both the role of α4 integrin and the therapeutic effect of HCA3551, a newly synthesized orally active small molecule α4 integrin antagonist, in the development of Theiler's murine encephalomyelitis virus-induced demyelinating disease (TMEV-IDD). The mRNA levels of α4 integrins were significantly up-regulated in the central nervous system (CNS) of mice with TMEV-IDD as compared with naive mice (*P < 0.05). HCA3551 treatment in the effector phase significantly suppressed both the clinical and histological development of TMEV-IDD. The number of infiltrating mononuclear inflammatory cells in the CNS was significantly decreased in the mice treated with HCA3551 (**P < 0.01). The labeling indices for CD68 antigen and the absolute cell numbers of TNF-α-producing CD4+ T cells and IFN-γ-producing CD8+ T cells were significantly decreased in the CNS of mice treated with HCA3551 (*P < 0.05). HCA3551 treatment in the effector phase might inhibit the binding of α4 integrin to vascular cell adhesion molecule-1, thereby decreasing the number of mononuclear cells in the CNS.

Chronic Cholestatic Liver Injury Attributable to Vedolizumab.

Drug-induced liver injury is a rare but clinically important diagnosis. Vedolizumab is an α4ß7 integrin inhibitor recently approved for use in patients with moderate-to-severe inflammatory bowel disease. Cases of hepatoxicity due to vedolizumab in the pre-marketing stage were rare, and all cases resolved upon drug withdrawal. We present here the first reported case of hepatotoxicity attributable to vedolizumab, which despite drug cessation persisted with chronic cholestatic liver injury.

Transarterial administration of integrin inhibitor loaded nanoparticles combined with transarterial chemoembolization for treating hepatocellular carcinoma in a rat model.

AIM: To compare the effect of transarterial chemoembolization (TACE) plus GRGDSP (Gly-Arg-Gly-Asp-Ser-Pro, integrin-inhibitor) loaded nanoparticles with TACE alone or TACE + GRGDSP in a rat model of liver tumor. METHODS: Morris hepatoma 3924A tumors were implanted in the livers of 30 ACI rats. The ACI rats were divided randomly into three groups (10 animals each). Tumor volume before treatment (V1) was examined by magnetic resonance imaging (MRI), and then, after laparotomy and placement of a PE-10 catheter into the hepatic artery, the following interventional protocols were performed: TACE (mitomycin C + lipiodol + degradable starch microspheres) + GRGDSP loaded nanoparticles for group A; TACE + GRGDSP for group B (control group 1); TACE alone for group C (control group 2). Tumor volume (V2) was assessed by MRI and the mean ratio of the post-treatment to pretreatment tumor volumes (V2/V1) was calculated. Immunohistochemical analysis was performed to assess the quantification of matrix metalloprotein 9 (MMP-9) and vascular endothelial growth factor (VEGF) positive tumor cells in each treatment group. RESULTS: The mean tumor growth ratios (V2/V1) were 1.3649 ± 0.1194 in group A, 2.0770 ± 0.1595 in group B, and 3.2148 ± 0.1075 in group C. Compared with groups B and C, group A showed a significant reduction in tumor volume. Lower expression of MMP-9 and VEGF in hepatocellular carcinoma was observed in group A than in groups B and C. The angiogenesis of tumor was evaluated using anti-VEGF antibodies, and the metastasis of tumor was assessed using anti-MMP-9 antibody. MMP-9 and VEGF were expressed in all specimens. The immunoexpression of these proteins was confirmed by the presence of red cytoplasmic staining in tumor cells. Lower expression of MMP-9 and VEGF in hepatocellular carcinoma was observed in group A than in groups B and C. CONCLUSION: Transarterial administration of integrin inhibitor loaded nanoparticles combined with TACE evidently retards tumor growth and intrahepatic metastases compared with TACE alone or TACE plus integrin inhibitor in an animal model of hepatocellular carcinoma.

5-aminomethyloxazolidine-2,4-dione hybrid α/ß-dipeptide scaffolds as inductors of constrained conformations: Applications to the synthesis of integrin antagonists.

Peptidomimetics represent an attractive starting point for drug discovery programs; in particular, peptidomimetics that result from the incorporation of a heterocycle may take advantage of increased enzymatic stability and higher ability to reproduce the bioactive conformations of the parent peptides, resulting in enhanced therapeutic potential. Herein, we present mimetics of the α4ß1 integrin antagonist BIO1211 (MPUPA-Leu-Asp-Val-Pro-OH), containing a aminomethyloxazolidine-2,4-dione scaffold (Amo). Interestingly, the retro-sequences PhCOAsp(OH)-Amo-APUMP including either (S)- or (R)-configured Amo displayed significant ability to inhibit the adhesion of α4ß1 integrin expressing cells, and remarkable stability in mouse serum. Possibly, the conformational bias exerted by the Amo scaffold determined the affinity for the receptors. These peptidomimetics could be of interest for the development of small-molecule agents effective against inflammatory processes and correlated autoimmune diseases.

Cisplatin, 5-fluorouracil, and cetuximab (PFE) with or without cilengitide in recurrent/metastatic squamous cell carcinoma of the head and neck: results of the randomized phase I/II ADVANTAGE trial (phase II part).

BACKGROUND: Recurrent and/or metastatic squamous cell carcinoma of the head and neck (R/M-SCCHN) overexpresses αvß5 integrin. Cilengitide selectively inhibits αvß3 and αvß5 integrins and is investigated as a treatment strategy. PATIENTS AND METHODS: The phase I/II study ADVANTAGE evaluated cilengitide combined with cisplatin, 5-fluorouracil, and cetuximab (PFE) in R/M-SCCHN. The phase II part reported here was an open-label, randomized, controlled trial investigating progression-free survival (PFS). Patients received up to six cycles of PFE alone or combined with cilengitide 2000 mg once (CIL1W) or twice (CIL2W) weekly. Thereafter, patients received maintenance therapy (cilengitide arms: cilengitide plus cetuximab; PFE-alone arm: cetuximab only) until disease progression or unacceptable toxicity. RESULTS: One hundred and eighty-two patients were treated. Median PFS per investigator read was similar for CIL1W + PFE, CIL2W + PFE, and PFE alone (6.4, 5.6, and 5.7 months, respectively). Accordingly, median overall survival and objective response rates were not improved with cilengitide (12.4 months/47%, 10.6 months/27%, and 11.6 months/36%, respectively). No clinically meaningful safety differences were observed between groups. None of the tested biomarkers (expression of integrins, CD31, Ki-67, vascular endothelial growth factor receptor 2, vascular endothelial-cadherin, type IV collagen, epidermal growth factor receptor, or p16 for human papillomavirus) were predictive of outcome. CONCLUSION: Neither of the cilengitide-containing regimens demonstrated a PFS benefit over PFE alone in R/M-SCCHN patients.

Inhibitory effects of recombinant RTS-jerdostatin on integrin α1ß1 function during adhesion, migration and proliferation of rat aortic smooth muscle cells and angiogenesis.

Jerdostatin, a short RTS-disintegrin cloned from venom gland mRNA of Protobothrops jerdonii, selectively blocks the adhesion of α1ß1 integrin to collagen IV. Integrin α1ß1 is highly expressed in smooth muscle cells (SMC) surrounding small blood vessels and vascular endothelial cells. Vascular SMC adhesion, migration and proliferation are important processes during normal vascular development. Using recombinant jerdostatin we have investigated the role of the α1ß1 integrin on the adhesion of vascular SMC to collagen IV, and the potential relevance of blocking this crucial component of focal adhesions as an anti-angiogenic strategy. Our results show that jerdostatin does not interact with canonical collagen-binding site on the isolated A-domain of the α1 integrin subunit. r-Jerdostatin inhibited the adhesion of RASMCs to immobilized CB3 fragment in a dose-dependent manner, triggering to round-up, retraction, and finally detachment of the cells. r-Jerdostatin did not affect the adhesion of human SMCs to CB3, presumably because the high expression of α2ß1 integrin compensated for α1ß1 integrin blockage by jerdostatin. r-Jerdostatin dose-dependently inhibited α1ß1 integrin-dependent HUVEC tube formation. However, VEGF-driven tube formation in the matrigel assay was only completely abolished when binding of integrin α2ß1 to collagen was also inhibited by the C-type lectin-like rhodocetin. As a whole, our work emphasizes the relevance of using specific inhibitors for dissecting the role of α1ß1 integrin in physiological and pathological conditions.

Neuropilin-1 modulates vascular endothelial growth factor-induced poly(ADP-ribose)-polymerase leading to reduced cerebrovascular apoptosis.

Cerebral ischemia is encompassed by cerebrovascular apoptosis, yet the mechanisms behind apoptosis regulation are not fully understood. We previously demonstrated inhibition of endothelial apoptosis by vascular endothelial growth factor (VEGF) through upregulation of poly(ADP-ribose)-polymerase (PARP) expression. However, PARP overactivation through oxidative stress can lead to necrosis. This study tested the hypothesis that neuropilin-1 (NP-1), an alternative VEGF receptor, regulates the response to cerebral ischemia by modulating PARP expression and, in turn, apoptosis inhibition by VEGF. In endothelial cell culture, NP-1 colocalized with VEGF receptor-2 (VEGFR-2) and acted as its coreceptor. This significantly enhanced VEGF-induced PARP mRNA and protein expression demonstrated by receptor-specific inhibitors and VEGF-A isoforms. NP-1 augmented the inhibitory effect of VEGF/VEGFR-2 interaction on apoptosis induced by adhesion inhibition through the αV-integrin inhibitor cRGDfV. NP-1/VEGFR-2 signal transduction involved JNK and Akt. In rat models of permanent and temporary middle cerebral artery occlusion, the ischemic cerebral hemispheres displayed endothelial and neuronal apoptosis next to increased endothelial NP-1 and VEGFR-2 expression compared to non-ischemic cerebral hemispheres, sham-operated or untreated controls. Increased vascular superoxide dismutase-1 and catalase expression as well as decreased glycogen reserves indicated oxidative stress in the ischemic brain. Of note, protein levels of intact PARP remained stable despite pro-apoptotic conditions through increased PARP mRNA production during cerebral ischemia. In conclusion, NP-1 is upregulated in conditions of imminent cerebrovascular apoptosis to reinforce apoptosis inhibition and modulate VEGF-dependent PARP expression and activation. We propose that NP-1 is a key modulator of VEGF maintaining cerebrovascular integrity during ischemia. Modulating the function of NP-1 to target PARP could help to prevent cellular damage in cerebrovascular disease.