One approach to understanding CLL is to investigate the nature of intracellular signals responsible for the development and prolonged survival of the malignant cells. 2 In this regard, signals generated by B-cell receptor (BCR) engagement are known to play an important role. 1 A key mediator of BCR-induced signaling is protein kinase C (PKC). [3][4][5][6][7][8][9] In CLL cells, this class of enzymes has been identified as a possible target of therapeutic intervention based on in vitro studies demonstrating that inhibition of these enzymes induces apoptosis. [10][11][12][13][14][15] Given the role of BCR signals in the survival and clonal expansion of CLL cells and the role of PKC(s) in the signaling pathways induced by BCR engagement, it follows that PKC(s) may play an important role in the BCR-induced survival of CLL cells.The PKC family is divided into 3 subgroups: the classical, which includes PKC␣, ␤I, ␤II, and ␥; the novel, which includes PKC␦, ⑀, , and ; and the atypical, which includes PKC and . These enzymes are activated by the presence of Ca 2ϩ , diacylglycerol, or other activating factors, 16 and they function in an array of cellular processes that can be specific for a particular cell type. In B cells, PKC, 5 PKC␤, 3,4,7,8 PKC␦,6 and PKC⑀ 9 play important roles in regulating signals generated by the BCR. With respect to CLL, active PKC␦ is thought to maintain cell survival downstream of phosphoinositol 3Ј-kinase. 15 Despite the potential of PKCs as therapeutic targets in CLL, [10][11][12][13][14][15] little is known about the relative levels and activities of the different isoforms known to be expressed within the malignant cells of this disease.In the present study, we show that PKC␤II is overexpressed in CLL cells and that the activity of this enzyme inversely correlates with CLL cell response to BCR engagement. Therefore, by regulating BCR signals important for malignant cell survival, PKC␤II may be a key factor in CLL progression. Materials and methods MaterialsMouse monoclonal and rabbit polyclonal anti-PKC␤II, monoclonal anti-PKC␤I, -PLC␥2, and -CD40 antibodies, rabbit anti-PKC␣, -PKC␦, -PKC, Mcl-1 and procaspase-8, and horseradish peroxidase-conjugated antimouse and anti-rabbit immunoglobulin antibodies were purchased from Santa Cruz Biotechnology (Insight Biotechnology, Middlesex, United Kingdom). Monoclonal anti-PKC␦ and anti-PKC⑀ antibodies were purchased from BD Biosciences (Oxford, United Kingdom). F(ab 2 )Ј fragments of goat anti-human IgM were purchased from Jackson ImmunoResearch Laboratories (Stratech, Soham, United Kingdom). Mouse anti-pS 180 -Bruton tyrosine kinase (Btk) and rabbit anti-Btk and anti-pY 759 -PLC␥2 antibodies were purchased from Cell Signaling Technology (New England Biolabs, Hitchin, Herts, United Kingdom). Purified recombinant PKC␣, PKC␤I, PKC␤II, PKC␦, PKC⑀, and PKC proteins and Ro32-0432 were purchased from Merck Biosciences (Nottingham, United Kingdom). Purified recombinant PKC and PKC proteins and mouse anti-ZAP-70 antibody were purchased from Upstate (Milton Ke...

No abstract

BackgroundDiesel exhaust inhalation causes cardiovascular dysfunction including impaired vascular reactivity, increased blood pressure, and arterial stiffness. We investigated the role of nitric oxide (NO) bioavailability in mediating these effects.Methods and ResultsIn 2 randomized double‐blind crossover studies, healthy nonsmokers were exposed to diesel exhaust or filtered air. Study 1: Bilateral forearm blood flow was measured during intrabrachial infusions of acetylcholine (ACh; 5 to 20 μg/min) and sodium nitroprusside (SNP; 2 to 8 μg/min) in the presence of the NO clamp (NO synthase inhibitor NG‐monomethyl‐l‐arginine (l‐NMMA) 8 μg/min coinfused with the NO donor SNP at 90 to 540 ng/min to restore basal blood flow). Study 2: Blood pressure, arterial stiffness, and cardiac output were measured during systemic NO synthase inhibition with intravenous l‐NMMA (3 mg/kg). Following diesel exhaust inhalation, plasma nitrite concentrations were increased (68±48 versus 41±32 nmol/L; P=0.006) despite similar l‐NMMA–induced reductions in basal blood flow (−20.6±14.7% versus −21.1±14.6%; P=0.559) compared to air. In the presence of the NO clamp, ACh and SNP caused dose‐dependent vasodilatation that was not affected by diesel exhaust inhalation (P>0.05 for both). Following exposure to diesel exhaust, l‐NMMA caused a greater increase in blood pressure (P=0.048) and central arterial stiffness (P=0.007), but reductions in cardiac output and increases in systemic vascular resistance (P>0.05 for both) were similar to those seen with filtered air.ConclusionsDiesel exhaust inhalation disturbs normal vascular homeostasis with enhanced NO generation unable to compensate for excess consumption. We suggest the adverse cardiovascular effects of air pollution are, in part, mediated through reduced NO bioavailability.Clinical Trial RegistrationURL: http://www.ClinicalTrials.gov. Unique identifiers: NCT00845767 and NCT01060930.

Meta-analyses have indicated that individuals with type 1 or type 2 diabetes are at increased risk of suffering a severe form of COVID-19 and have a higher mortality rate than the non-diabetic population. Patients with diabetes have chronic, low-level systemic inflammation, which results in global cellular dysfunction underlying the wide variety of symptoms associated with the disease, including an increased risk of respiratory infection. While the increased severity of COVID-19 amongst patients with diabetes is not yet fully understood, the common features associated with both diseases are dysregulated immune and inflammatory responses. An additional key player in COVID-19 is the enzyme, angiotensin-converting enzyme 2 (ACE2), which is essential for adhesion and uptake of virus into cells prior to replication. Changes to the expression of ACE2 in diabetes have been documented, but they vary across different organs and the importance of such changes on COVID-19 severity are still under investigation. This review will examine and summarise existing data on how immune and inflammatory processes interplay with the pathogenesis of COVID-19, with a particular focus on the impacts that diabetes, endothelial dysfunction and the expression dynamics of ACE2 have on the disease severity.