Despite great interest, the mechanism of neutrophil extracellular traps (NETs) release is not fully understood and some aspects of this process, e.g. the role of reactive nitrogen species (RNS), still remain unclear. Therefore, our aim was to investigate the mechanisms underlying RNS-induced formation of NETs and contribution of RNS to NETs release triggered by various physiological and synthetic stimuli. The involvement of RNS in NETs formation was studied in primary human neutrophils and differentiated human promyelocytic leukemia cells (HL-60 cells). RNS (peroxynitrite and nitric oxide) efficiently induced NETs release and potentiated NETs-inducing properties of platelet activating factor and lipopolysaccharide. RNS-induced NETs formation was independent of autophagy and histone citrullination, but dependent on the activity of phosphoinositide 3-kinases (PI3K) and myeloperoxidase, as well as selective degradation of histones H2A and H2B by neutrophil elastase. Additionally, NADPH oxidase activity was required to release NETs upon stimulation with NO, as shown in NADPH-deficient neutrophils isolated from patients with chronic granulomatous disease. The role of RNS was further supported by increased RNS synthesis upon stimulation of NETs release with phorbol 12-myristate 13-acetate and calcium ionophore A23187. Scavenging or inhibition of RNS formation diminished NETs release triggered by these stimuli while scavenging of peroxynitrite inhibited NO-induced NETs formation. Our data suggest that RNS may act as mediators and inducers of NETs release. These processes are PI3K-dependent and ROS-dependent. Since inflammatory reactions are often accompanied by nitrosative stress and NETs formation, our studies shed a new light on possible mechanisms engaged in various immune-mediated conditions. Keywords Autophagy • Neutrophil extracellular traps • Nitric oxide • Peroxynitrite • Phosphoinositide 3-kinases • Reactive nitrogen species Abbreviations 3-MA 3-Methyladenine ABAH Aminobenzoic acid hydrazide AKT Protein kinase B CGD Chronic granulomatous disease CI Calcium ionophore A23187 DHR 123 Dihydrorhodamine 123 DPI Diphenyleneiodonium ERK Extracellular signal-regulated kinases IL Interleukin LC3 protein Light chain 3 protein L-NAME N-nitroarginine methyl ester LPS Lipopolysaccharide MAPK Mitogen-activated protein kinases MPO Myeloperoxidase NAC N-acetylcysteine NE Neutrophil elastase NEi Neutrophil elastase inhibitor GW 311616A NETs Neutrophil extracellular traps NBT Nitroblue tetrazolium NO Nitric oxide NOS Nitric oxide synthase Cellular and Molecular Life Sciences Malgorzata Wachowska and Urszula Demkow have contributed equally.

Glucose-regulated protein 78 (GRP78) is an endoplasmic reticulum (ER)-resident chaperone and a major regulator of the unfolded protein response (UPR). Accumulating evidence indicate that GRP78 is overexpressed in many cancer cell lines, and contributes to the invasion and metastasis in many human tumors. Besides, GRP78 upregulation is detected in response to different ER stress-inducing anticancer therapies, including photodynamic therapy (PDT). This study demonstrates that GRP78 mRNA and protein levels are elevated in response to PDT in various cancer cell lines. Stable overexpression of GRP78 confers resistance to PDT substantiating its cytoprotective role. Moreover, GRP78-targeting subtilase cytotoxin catalytic subunit fused with epidermal growth factor (EGF-SubA) sensitizes various cancer cells to Photofrin-mediated PDT. The combination treatment is cytotoxic to apoptosis-competent SW-900 lung cancer cells, as well as to Bax-deficient and apoptosis-resistant DU-145 prostate cancer cells. In these cells, PDT and EGF-SubA cytotoxin induce protein kinase R-like ER kinase and inositol-requiring enzyme 1 branches of UPR and also increase the level of C/EBP (CCAAT/enhancer-binding protein) homologous protein, an ER stress-associated apoptosis-promoting transcription factor. Although some apoptotic events such as disruption of mitochondrial membrane and caspase activation are detected after PDT, there is no phosphatidylserine plasma membrane externalization or DNA fragmentation, suggesting that in DU-145 cells the late apoptotic events are missing. Moreover, in SW-900 cells, EGF-SubA cytotoxin potentiates PDT-mediated cell death but attenuates PDT-induced apoptosis. In addition, the cell death cannot be reversed by caspase inhibitor z-VAD, confirming that apoptosis is not a major cell death mode triggered by the combination therapy. Moreover, no typical features of necrotic or autophagic cell death are recognized. Instead, an extensive cellular vacuolation of ER origin is observed. Altogether, these findings indicate that PDT and GRP78-targeting cytotoxin treatment can efficiently kill cancer cells independent on their apoptotic competence and triggers an atypical, non-apoptotic cell death.

The adult mouse heart possesses an extensive lymphatic plexus draining predominantly the subepicardium and the outer layer of the myocardial wall. However, the development of this plexus has not been entirely explored, partially because of the lack of suitable methods for its visualization as well as prolonged lymphatic vessel formation that starts prenatally and proceeds during postnatal stages. Also, neither the course nor location of collecting vessels draining lymph from the mouse heart have been precisely characterized. In this article, we report that murine cardiac lymphatic plexus development that is limited prenatally only to the subepicardial area, postnatally proceeds from the subepicardium toward the myocardial wall with the base-to-apex gradient; this plexus eventually reaches the outer half of the myocardium with a predominant location around branches of coronary arteries and veins. Based on multiple marker immunostaining, the molecular marker-phenotype of cardiac lymphatic endothelial cells can be characterized as: Prox-1 1 , Lyve-1 1 , VEGFR3 1 , Podoplanin 1 , VEGFR2 1 , CD144 1 , Tie2 1 , CD31 1 , vWF 2 , CD34 2 , CD133 2 . There are two major collecting vessels: one draining the right and left ventricles along the left conal vein and running upwards to the left side of the pulmonary trunk and further to the nearest lymph nodes (under the aortic arch and near the trachea), and the other one with its major branch running along the left cardiac vein and further on the surface of the coronary sinus and the left atrium to paratracheal lymph nodes. The extracardiac collectors gain the smooth muscle cell layer during late postnatal stages.

The p.Ser165Phe mutation is a likely cause of IKSHD.

The role of the cardiac lymphatic system has been recently appreciated since lymphatic disturbances take part in various heart pathologies. This review presents the current knowledge about normal anatomy and structure of lymphatics and their prenatal development for a better understanding of the proper functioning of this system in relation to coronary circulation. Lymphatics of the heart consist of terminal capillaries of various diameters, capillary plexuses that drain continuously subendocardial, myocardial, and subepicardial areas, and draining (collecting) vessels that lead the lymph out of the heart. There are interspecies differences in the distribution of lymphatic capillaries, especially near the valves, as well as differences in the routes and number of draining vessels. In some species, subendocardial areas contain fewer lymphatic capillaries as compared to subepicardial parts of the heart. In all species there is at least one collector vessel draining lymph from the subepicardial plexuses and running along the anterior interventricular septum under the left auricle and further along the pulmonary trunk outside the heart and terminating in the right venous angle. The second collector assumes a different route in various species. In most mammalian species the collectors run along major branches of coronary arteries, have valves and a discontinuous layer of smooth muscle cells.