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To better understand the etiology of inflammatory breast cancer (IBC) and identify potential therapies, we studied genomic alterations in IBC patients. Targeted, next-generation sequencing (NGS) was performed on cell-free DNA (cfDNA) (n = 33) and paired DNA from tumor tissues (n = 29) from 32 IBC patients. We confirmed complementarity between cfDNA and tumor tissue genetic profiles. We found a high incidence of germline variants in IBC patients that could be associated with an increased risk of developing the disease. Furthermore, 31% of IBC patients showed deficiencies in the homologous recombination repair (HRR) pathway (BRCA1, BRCA2, PALB2, RAD51C, ATM, BARD1) making them sensitive to poly (ADP-ribose) polymerase (PARP) inhibitors. We also characterized the tumor-infiltrating lymphocytes (TILs) in tumor tissue biopsies by studying several markers (CD4, CD8, FoxP3, CD20, PD-1, and PD-L1) through immunohistochemistry (IHC) staining. In 7 of 24 (29%) patients, tumor biopsies were positive for PD-L1 and PD-1 expression on TILs, making them sensitive to PD-1/PD-L1 blocking therapies. Our results provide a rationale for considering PARP inhibitors and PD-1/PDL1 blocking immunotherapy in qualifying IBC patients.

Background & Aims In the West, early gastric cancer is increasingly managed with endoscopic resection (ER). This is, however, based on the assumption that the low prevalence and risk of lymph node metastases observed in Asian patients is applicable to patients in the United States. We sought to evaluate the frequency of and factors associated with metastasis of early gastric cancers to lymph nodes, and whether the Japanese ER criteria are applicable to patients in the US. Methods We performed a retrospective study of 176 patients (mean age 68.5 years; 59.1% male; 58.5% white) who underwent surgical resection with lymph node dissection of T1 and Tis gastric adenocarcinomas, staged by pathologists, at 7 tertiary care centers in the US from January 1, 1999, through December 31, 2016. The frequency of lymph node metastases and associated risk factors were determined. Results The mean size of gastric adenocarcinomas was 23.0 ± 16.6 mm—most were located in the lower-third of the stomach (67.0%), invading the submucosa (55.1%), and moderately differentiated (31.3%). Lymphovascular invasion was observed in 18.2% of lesions. Overall, 20.5% of patients had lymph node metastases. Submucosal invasion (odds ratio, 3.9; 95% CI, 1.4–10.7) and lymphovascular invasion (odds ratio, 4.6; 95% CI, 1.8–12.0) were independently associated with increased risk of metastasis to lymph nodes. The frequency of lymph node metastases among patients fulfilling standard and expanded Japanese criteria for ER were 0 and 7.5%, respectively. Conclusions The frequency of lymph node metastases among patients with early gastric cancer in a US population is higher than that of published Asian series. However, early gastric cancer lesions that meet the Japanese standard criteria for ER are associated with negligible risk of metastasis to lymph nodes, so ER can be recommended for definitive therapy. Expanded criteria cancers appear to have a higher risk of metastasis to lymph nodes, so ER may be considered for select cases.

In the gastro-entero-pancreatic (GEP) tract, neuroendocrine neoplasms (NENs) include well differentiated neuroendocrine tumors (NETs) and high-grade NE carcinomas (NECs), which are thought to make up separate and mutually exclusive tumor entities. Little is known, however, as to whether there may be any pathogenetic link between them. Clustering analysis of a 10-gene panel generated from a previously reported next-generation sequencing analysis on 48 GEP-NENs with clinical annotations was used in the study. Unsupervised cluster analysis showed three histology-independent clusters, namely, C1, C2, and C3, which accounted for 44% of patients but the entire array of mutations. All but two NECs fell into the clusters, yet with different prevalence rates (p

We present a low-grade follicular lymphoma case with highly unusual ancillary study results. The patient is a 50-year-old female with a 4.3 x 3.8 x 2.2 cm left inguinal mass, from which fine needle aspiration and excisional biopsy specimens were obtained. H&E sections showed effacement of the lymph node architecture by closely packed follicles comprised of mainly centrocytes and without tingible body macrophages. Immunohistochemical stains revealed the follicle cells positive for CD20, PAX5, BCL6, CD10 (weak), and BCL2 (weak), while CD3 highlighted small T lymphocytes mainly in the interfollicular areas.

The interaction between ERK2 and its substrates is critically mediated by two domains, the common docking (CD) D-domain and DEF-binding pocket (DBP) domain. Previous studies have suggested that ERK2 is not only necessary to drive hematopoietic and myelo-erythroid development, but it is also important for the pathogenesis of hematological cancers, as revealed by recurrent ERK2 somatic mutations in many types of lymphoma and leukemia. Here we show that the activation of ERK2 in JAK2V617F-driven myeloproliferative neoplasm (MPN) enhance polycythemia vera (PV) progression from erythrocytosis to myelofibrosis when ERK2-DBP binding capacity is disabled. Conversely, targeting the ERK2 D-domain preserves ERK2 catalytic function while reducing outgrowth and proliferation of human and murine MPN cell lines. To determine whether ERK2 binding domains play a role in the pathogenesis of JAK2V617F-driven MPN, we generated an ERK2-Y261A (Erk2 Y261A) mutant knockin mouse model in which the ERK2-DBP domain was inactivated, but ERK2 kinase activity and D-domain function was preserved. We observed splenomegaly in Erk2 Y261A/Y261A, characterized by a 10-fold expansion of CD44+/Ter119+ primitive erythroblasts and Ter119+CD44+/ FSC hi immature erythroid progenitors. We then transplanted Jak2 V617F-expressing ERK2 wildtype (WT), knockout (KO) or DBP hematopoietic progenitors (HSPCs) into irradiated, immunodeficient mice (Rag2 −/−Il2rg −/−) and observed disease resembling human PV, with elevated RBC counts, hematocrit, and hemoglobin levels. ERK2-DBP mutant recipients exhibited mild but sustained erythrocytosis with a prevalence of circulating GFP+ monocytes and neutrophils. At 12-weeks post-transplantation, ERK2-DBP mutant recipients had significant splenic burden and decreased bone marrow cellularity relative to WT and KO recipients. Reticulin staining confirmed progression towards myelofibrosis with interstitial infiltration in both the BM and the spleen of ERK2 DBP mutant recipients. To understand the molecular basis of ERK-DBP domain in JAK2V617F-driven MPN, we performed in vitro colony forming unit assay to assess the clonogenic potential of JAK2V617F-expressing HSPCs in cytokine supplemented-methylcellulose supporting myeloid or erythroid progenitor development. Ectopic JAK2V617F expression markedly reduced colony formation by both ERK2 wildtype and knockout HSPCs. On the other hand, JAK2V617F expression did not reduce colony formation by ERK2-DBP HSPCs. These differences were not evident in methylcellulose cultures that supported erythroid development, suggesting that disabling ERK-DBP binding capacity primarily affects the myeloid lineage. Furthermore, we found that JAK2V617F increased senescence associated β-galactosidase (SA-βGa) activity in ERK2-WT HSPCs. SA-βGal activity was modestly affected by ERK deficiency but was strongly attenuated by the ERK2-DBP mutation, supporting the notion that ERK2-DBP domain promotes oncogene-induced senescence (OIS). Previously, we identified transcription factor, Early growth response 1 (Egr1) which interacts with ERK2-DBP domain and plays a critical role as a tumor suppressor in myeloid neoplasms. We observed that JAK2V617F expression failed to suppress colony formation and senescence by Egr1-deficient HSPCs. The ability of EGR1 to restore these effects is abrogated by inactivating the DEF motif (EGR1-Y252A). Together, this data demonstrates that the interaction between ERK2-DBP and Egr1 is required for JAK2V617F-mediated colony suppression and senescence induction. Finally, to determine whether ERK-D domain acts to promote progression by targeting substrates distinct from those that bind to the DBP domain, we developed an inhibitor (#76) of the ERK-D domain. Indeed, 76 spared ERK phosphorylation and EGR1 induction but impaired RSK phosphorylation, a critical D-domain substrate involved in cancer progression. Moreover, 76 suppressed colony formation by JAK2V61F-expressing HSPCs akin to the active site MEK/ERK inhibitor, U0126. By altering the 4-ethoxybenylidene moiety of 76, we were able to enhance anti-proliferative effects of the parent compound against human MPN cell lines, SET-2, UKE-1, and Ku812. Our findings identify ERK2-domain specific roles in the pathogenesis of JAK2V617F driven MPN and supports a novel therapeutic approach to targeting JAK2 and MAPK dependent MPN. Disclosures Levine: Celgene: Research Funding; QIAGEN: Membership on an entity's Board of Directors or advisory committees; Auron: Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria; Mission Bio: Membership on an entity's Board of Directors or advisory committees; Zentalis: Membership on an entity's Board of Directors or advisory committees; Ajax: Membership on an entity's Board of Directors or advisory committees; C4 Therapeutics: Membership on an entity's Board of Directors or advisory committees; Incyte: Consultancy; Lilly: Honoraria; Janssen: Consultancy; Astellas: Consultancy; Gilead: Honoraria; Prelude: Membership on an entity's Board of Directors or advisory committees; Isoplexis: Membership on an entity's Board of Directors or advisory committees; Morphosys: Consultancy; Roche: Honoraria, Research Funding; Imago: Membership on an entity's Board of Directors or advisory committees. Wiest: Janssen Pharmaceuticals: Research Funding.

The growth of disseminated tumor cells (DTCs) into metastatic lesions depends on the establishment of a favorable microenvironment in the stroma of the target organs. Here we show that mice treated with anakinra, an antagonist of the IL-1β receptor (IL-1R), or harboring a targeted deletion of IL-1R are significantly less prone to develop bone tumors when inoculated in the arterial circulation with human prostate cancer (PCa) cells expressing IL-1β. Interestingly, human mesenchymal stem cells (hMSCs) exposed in vitro to medium conditioned by IL-1β-expressing cancer cells responded by up regulating S100A4, a marker of cancer-associated fibroblasts (CAFs), and this effect was blocked by anakinra. Analogously, the stroma adjacent to skeletal metastases generated in mice by IL-1β-expressing cancer cells showed a dramatic increase in S100A4, COX-2 and the alteration of thirty tumor-related genes as measured by Nanostring analysis. These effects were not observed in the stroma associated to the rare and much smaller metastases generated by the same cells in IL-1R knockout animals, confirming that tumor-secreted IL-1β generates skeletal CAFs and conditions the surrounding bone microenvironment. In skeletal lesions from patients with metastatic PCa, histological and molecular analyses revealed that IL-1β is highly expressed in cancer cells in which the androgen receptor (AR) is not detected (AR−) whereas this cytokine is uniformly absent in the AR-positive (AR+) metastatic cells. The stroma conditioned by IL-1β-expressing cancer cells served as a supportive niche also for coexisting IL-1β-lacking cancer cells, which are otherwise unable to generate tumors after independently seeding the skeleton of mice. This niche is established very early following tumor seeding and hints to a role of IL-1β in promoting early colonization of PCa at the skeletal level.

Background: The rarity of neuroendocrine malignancies limits the ability to develop new therapies and thus a better understanding of the underlying biology is critical. Methods: Through a prospective, IRB-approved protocol, patients with neuroendocrine malignancies underwent next-generation sequencing of their tumours to detect somatic mutations (SMs) in 50 cancer-related genes. Clinicopathologic correlation was made among poorly differentiated neuroendocrine carcinomas (NECs/poorly differentiated histology and Ki-67 >20%) and pancreatic neuroendocrine tumours (PanNETs/Ki67 ⩽20%) and non-pancreatic neuroendocrine tumours (NP-NETs/Ki67 ⩽20%). Results: A total of 77 patients were enrolled, with next-generation sequencing results available on 63 patients. Incidence of SMs was 83% (19 out of 23) in poorly differentiated NECs, 45% (5 out of 11) in PanNETs and 14% (4 out of 29) in NP-NETs. TP53 was the most prevalent mutation in poorly differentiated NECs (57%), and KRAS (30%), PIK3CA/PTEN (22%) and BRAF (13%) mutations were also found. Small intestinal neuroendocrine tumours (Ki67

In order to better understand the etiology of inflammatory breast cancer (IBC), we performed a retrospective study to evaluate genomic alterations in 32 IBC patients using circulating DNA from blood. In 20 patients, mutation analyses were also conducted on tumor tissue or tumor cells from pleural effusions; in 15 of these patients, blood and tissue or pleural effusions were collected at the same time. Next generation sequencing (NGS) and a panel of 93 breast cancer related genes (Qiagen) were used for these studies. We found that of the 32 total patients, 11 (34.4%) carried at least one putative pathogenic germline variant, and another 8 patients (25%) carried at least one likely pathogenic germline variant. Ten patients (31.3%) carried only germline variants of uncertain significance and in 3 patients (9.4%) germline variants were not detected. Putative germline pathogenic variants were observed in the BRCA2 (2/32), TP53 (2/32), BRCA1 (1/32), PALB2 (1/32), CHEK2 (1/32), ATM (1/32), PMS1 (1/32), MUTYH (1/32), and MSH2 (1/32) genes. In addition, putative germline likely pathogenic variants were observed in the BARD1 (10/32), RB1 (2/32), APC (1/32), FANCC (1/32), AR (1/32), RAD51C (1/32), RAD51D (1/32) and CASP8 (1/32) genes. Most of the patients in our study had a family history of cancer and seventeen of the patients (53.1%) had family history of breast cancer in particular. Of those patients, 7 had a family history of breast cancer at a young age ( Citation Format: Jennifer S. Winn, Zachary Hasse, Jianming Pei, Michael Slifker, Sebastian M. Arisi-Fernandez, Jacqueline N. Talarchek, Elias Obeid, Karthik Devarajan, Hong Wu, Yulan Gong, Massimo Cristofanilli, R.Katherine Alpaugh, Sandra Viviana Fernandez. Germline and somatic variants in patients with inflammatory breast cancer (IBC) detected using cell-free DNA [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P5-03-11.

We studied genomic alterations in 19 inflammatory breast cancer (IBC) patients with advanced disease using samples of tissue and paired blood serum or plasma (cell-free DNA, cfDNA) by targeted next generation sequencing (NGS). At diagnosis, the disease was triple negative (TN) in eleven patients (57.8%), ER+ Her2- IBC in six patients (31.6%), ER+ Her2+ IBC in one patient (5.3%), and ER- Her2+ IBC in one other patient (5.3%). Pathogenic or likely pathogenic variants were frequently detected in TP53 (47.3%), PMS2 (26.3%), MRE11 (26.3%), RB1 (10.5%), BRCA1 (10.5%), PTEN (10.5%) and AR (10.5%), other affected genes included PMS1, KMT2C, BRCA2, PALB2, MUTYH, MEN1, MSH2, CHEK2, NCOR1, PIK3CA, ESR1 and MAP2K4. In 15 of the 19 patients in which tissue and paired blood were collected at the same time point, 80% of the variants detected in tissue were also detected in the paired cfDNA. Higher concordance between tissue and cfDNA was found for variants with higher allele fraction in tissue (AFtissue &ge, 5%). Furthermore, 86% of the variants detected in cfDNA were also detected in paired tissue. Our study suggests that the genetic profile measured in blood cfDNA is complementary to that of tumor tissue in IBC patients.

292 Background: Few studies have characterized the molecular drivers of NET growth and mechanisms differentiating poorly differentiated (PD) and well differentiated (WD) NETs. We explored the role of dysregulated transcriptome as the principal molecular mechanism of NETs with the goal to identify novel targets and biomarkers of differentiation. Methods: With IRB approval, de-identified, formalin fixed NET samples were used to extract total RNA for transcriptome analysis. All pathology specimens were centrally reviewed. Gene expression profiles of 774 genes were obtained using nCounter platform (PanCancer pathway panel, Nanostring TechnologiesTM). The resulting count data was voom normalized and differentially expressed genes between PD and WD NETs were identified using linear modeling methods available in R-Bioconductor LIMMA package. Candidate genes with potential therapeutic implications were validated in tissue microarrays by immunohistochemistry (IHC). Results: Analysis of gene count data between 16 PD and 23 WD NETs resulted in 154 differentially expressed genes on the 774 gene panel (FDR < 10% and 2 fold change (FC) up- or down-regulated), some of which may be potential drug targets (Figure 1). E.g. Enhancer of zeste homolog 2 (EZH2), a histone methyltransferase responsible for transcriptional repression, and CHK1, a G2/M cell cycle regulator, were upregulated in PD compared to WD NETs (2.7 and 3.1 FC, respectively) and serine/threonine-protein kinase PAK 3, involved in cytoskeleton reorganization, was upregulated in WD NETs (3.4 FC). IHC staining also suggested overexpression of EZH2 and its enzymatic substrate H3K27me in PD NETs (p < 0.001). PAK 3, another novel therapeutic candidate overexpressed in WD NETs (p < 0.001) was confirmed using IHC, validating the transcriptome analysis at protein level. Conclusions: These findings, combined with previously reported pathway analysis (Vijayvergia et.al 2017)], highlight biological differences between PD and WD NETs and serve as a platform for future research. They also support investigation of novel drugs that inhibit activity of EZH2 (e.g. EPZ6438) in PD NETs and PAK3 (e.g FRAX597) in WD NETs.

Rationale: The cytosolic protease calpain has been recently implicated in the vascular remodeling of angiotensin II (Ang II) type 1 receptor (AT 1 R) signaling. The role of Ang II/AT 1 R/calpain signaling on endothelial function, an important and early determinant of vascular pathology, remains though totally unknown. Accordingly, we investigated the role of calpain in the endothelial dysfunction of Ang II. Objective: To demonstrate a mechanistic role for calpain in the endothelial dysfunction induced by Ang II/AT 1 R signaling. To establish endothelial-expressed calpains as an important target of AT 1 R signaling. Methods and Results: Subchronic administration of nonpressor doses of Ang II to rats and mice significantly increased vascular calpain activity via AT 1 R signaling. Intravital microscopy studies revealed that activation of vascular expressed calpains causes endothelial dysfunction with increased leukocyte–endothelium interactions and albumin permeability in the microcirculation. Western blot and immunohistochemistry studies confirmed that Ang II/AT 1 R signaling preferentially activates the constitutively expressed μ-calpain isoform and demonstrated a calpain-dependent degradation of IκBα, along with upregulation of nuclear factor κB–regulated endothelial cell adhesion molecules. These physiological and biochemical parameters were nearly normalized following inhibition of AT 1 R or calpain in vivo. RNA silencing studies in microvascular endothelial cells, along with knockout and transgenic mouse studies, further confirmed the role of μ-calpain in the endothelial adhesiveness induced by Ang II. Conclusions: This study uncovers a novel role for calpain in the endothelial dysfunction of Ang II/AT 1 R signaling and establishes the calpain system as a novel molecular target of the vascular protective action of renin–angiotensin system inhibition. Our results may have significant clinical implications in vascular disease.

Increased permeability to albumin is a well-known feature of diabetic microvasculature and a negative prognostic factor of vascular complications. The mechanisms responsible for loss of the physiological albumin barrier in diabetic organs remain only partially understood. We have recently demonstrated that the protease μ-calpain is activated in hyperglycemia, which causes endothelial dysfunction and vascular inflammation. In the present study, we investigated whether μ-calpain is involved in the hyperpermeability of the diabetic vasculature. We also investigated the mechanistic roles of hyperglycemia and leukocyte adhesion in this process. Albumin permeability in the intact microcirculation of the Zucker diabetic fatty (ZDF) rat was quantified by intravital microscopy. Extravasation of albumin in the microcirculation of ZDF rats was significantly increased when compared with nondiabetic Zucker lean (ZL) rats. Microvascular albumin leakage was prevented by either antisense depletion of μ-calpain or pharmacological inhibition of calpain in vivo. Calpain inhibition also attenuated urinary albumin excretion in ZDF rats. Glucose concentrations in the range of those found in the blood of ZDF rats increased albumin permeability in nondiabetic ZL rats. Thus, this demonstrates a mechanistic role for hyperglycemia in the hypermeability of diabetes. Depletion of polymorphonuclear leukocytes in vivo failed to prevent glucose-induced hypermeability, which suggests that hyperglycemia can disrupt the physiological endothelial cell barrier of the microcirculation, even in the absence of increased overt leukocyte-endothelium interactions.

Cardiovascular complications are the leading cause of morbidity and mortality in diabetic patients. Endothelial dysfunction with impaired endothelial nitric oxide (NO) synthase (eNOS) activity is a widely accepted cause of diabetic vasculopathy. The mechanisms of endothelial dysfunction in diabetes remain elusive, thus limiting effective therapeutic interventions. We report novel evidence demonstrating that the calcium-dependent protease calpain causes endothelial dysfunction and vascular inflammation in the microcirculation of the ZDF (Zucker diabetic fatty) rat, a genetic rat model of type 2 diabetes. We found evidence of increased calpain activity and leukocyte trafficking in the microcirculation of ZDF rats. Inhibition of calpain activity significantly attenuated leukocyte-endothelium interactions in the vasculature of ZDF rats. Expression of cell adhesion molecules in the vascular endothelium of ZDF rats was consistently increased, and it was suppressed by calpain inhibition. In vivo measurement of endothelial NO availability demonstrated a 60% decrease in NO levels in the microcirculation of diabetic rats, which was also prevented by calpain inhibition. Immunoprecipitation studies revealed calpain-dependent loss of association between eNOS and the regulatory protein heat shock protein 90. Collectively, these data provide evidence for a novel mechanism of endothelial dysfunction and vascular inflammation in diabetes. Calpains may represent a new molecular target for the prevention and treatment of diabetic vascular complications.

Cu-Al-Zn alloys with different stacking fault energy (SFE) were processed by surface mechanical attrition treatment (SMAT) at cryogenic temperature (CT), mechanical properties of gradient structured Cu-Al-Zn alloys were investigated in this study. Al and Zn content in alloys, which result in the decrease of SFE, can contribute to the increase in strength. Cu-4.5wt%Al-14.3wt%Zn alloy with the lower SFE shows that the strength increased, the ductility did not decrease significantly with increasing processing time, and the strength can be improved by a thicker gradient structure (GS) layer. The better combination of strength and ductility was achieved in Cu-4.5wt%Al-14.3wt%Zn alloy with lower SFE.

302 Background: NETs lack mutations in the “classical” signaling pathways but share mutations in regulators of gene expression (Jiao; 2011). We compared gene expression in PD & WD NETs to identify novel targets and biomarkers of differentiation. Methods: High quality RNA, extracted from paraffin blocks of deidentified NETs under an IRB-approved protocol, was profiled using a 770 gene panel (nCounter PanCancer pathway, Nanostring Technologies). The resulting data was used to identify the differentially expressed genes between PD and WD NETs using limma software (Ritchie; 2015). Gene Set Enrichment Analysis (Subramanian; 2005) identified differential pathway enrichment by calculating a Normalized Enrichment Score (NES). Results: Analysis of 16 PD and 23 WD NET samples identified 154 genes as extreme outliers ( > 2 fold up/downregulation between the subtypes). Compared to WD NETS, drug targets of interest overexpressed in PD NETs were histone lysine methyltransferase EZH2, and a cell cycle regulator CHEK1 (6.5x and 8.1x, respectively, p < 0.001). In contrast, serine/threonine protein kinase PAK 3 was upregulated in WD (10.6x, p < 0.001). These and other biomarkers will be further validated by immunolabeling of tissue sections. We also found differential enrichment of canonical pathways in PD versus WD NETs (table). Conclusions: Extreme outlier transcripts identified in PD & WD NETs support investigation of inhibitors of EZH2 (e.g. EPZ6438) and CHEK1 (e.g. LY2606368) in PD and PAK3(e.g. FRAX597) in WD NETs. Genes involved in cell cycle regulation and DNA repair in PD NETs and calcium / G protein coupled receptor signaling in WD NET account for biological differences between the 2 molecular subtypes and warrant future investigation as classifiers for NETs. Our findings provide mechanistic insights into the biology of NET and targets for therapy with direct clinical implications.[Table: see text]

Resuscitation from hemorrhagic shock induces endothelial dysfunction and activates inflammatory cascades leading to organ damage. Following restoration of blood flow to ischemic vascular beds, leukocyte–endothelium interactions leading to leukocyte infiltration into the vascular wall occur very early due, in part, to the loss of endothelium-derived nitric oxide (NO). The mechanism by which ischemia–reperfusion injury impairs endothelium-derived NO is not completely understood. We hypothesized that inhibition of Rho-kinase could exert beneficial effects following hemorrhagic shock by preserving endothelial function and attenuating leukocyte trafficking in the microcirculation. Using intravital microscopy, we found that resuscitation from hemorrhage acutely increased the number of rolling and adherent leukocytes in the mouse splanchnic microcirculation. Treatment of mice with the Rho-kinase inhibitor fasudil, markedly attenuated leukocyte–endothelium interaction in response to hemorrhage/reinfusion. The beneficial effect of fasudil was not observed in endothelial nitric oxide synthase (eNOS)−/− mice. In conclusion, inhibition of Rho-kinase prevents inflammatory leukocyte trafficking in the microcirculation via an eNOS-dependent mechanism. Our data support a role for Rho-kinase inhibitors in the treatment of ischemia–reperfusion injury.

This study reports on what we believe are novel mechanism(s) of the vascular protective action of adiponectin. We used intravital microscopy to measure leukocyte-endothelium interactions in adiponectin-deficient (Ad(-/-)) mice and found that adiponectin deficiency was associated with a 2-fold increase in leukocyte rolling and a 5-fold increase in leukocyte adhesion in the microcirculation. Measurement of endothelial NO (eNO) revealed that adiponectin deficiency drastically reduced levels of eNO in the vascular wall. Immunohistochemistry demonstrated increased expression of E-selectin and VCAM-1 in the vascular endothelium of Ad(-/-) mice. Systemic administration of the recombinant globular adiponectin domain (gAd) to Ad(-/-) mice significantly attenuated leukocyte-endothelium interactions and adhesion molecule expression in addition to restoring physiologic levels of eNO. Importantly, prior administration of gAd also protected WT mice against TNF-alpha-induced leukocyte-endothelium interactions, indicating a pharmacologic action of gAd. Mechanistically, blockade of eNOS with N(omega)-nitro-L-arginine methyl ester ( L-NAME) abolished the inhibitory effect of gAd on leukocyte adhesion, demonstrating the obligatory role of eNOS signaling in the antiinflammatory action of gAd. We believe this is the first demonstration that gAd protects the vasculature in vivo via increased NO bioavailability with suppression of leukocyte-endothelium interactions. Overall, we provide evidence that loss of adiponectin induces a primary state of endothelial dysfunction with increased leukocyte-endothelium adhesiveness.