Granzymes (Grs) are serine proteases mainly produced by cytotoxic lymphocytes and are traditionally considered to cause apoptosis in tumor cells and virally infected cells. However, the cytotoxicity ...of several Grs is currently being debated, and additional, predominantly extracellular, functions of Grs in inflammation are emerging. Extracellular soluble Grs are elevated in the circulation of patients with autoimmune diseases and infections. Additionally, Grs are expressed by several types of immune cells other than cytotoxic lymphocytes. Recent research has revealed novel immunomodulatory functions of Grs. In this review, we provide a comprehensive overview on the role of Grs in inflammation, highlighting their role in cytokine induction and processing.
PEGylation of lipid-based nanoparticles and other nanocarriers is widely used to increase their stability and plasma half-life. However, either pre-existing or de novo formed anti-PEG antibodies can ...induce hypersensitivity reactions and accelerated blood clearance through binding to the nanoparticle surfaces, leading to activation of the complement system.
In this study, we investigated the consequences and mechanisms of complement activation by anti-PEG antibodies interacting with different types of PEGylated lipid-based nanoparticles. By using both liposomes loaded with different (model) drugs and LNPs loaded with mRNA, we demonstrate that complement activation triggered by anti-PEG antibodies can compromise the bilayer/surface integrity, leading to premature drug release or exposure of their mRNA contents to serum proteins. Anti-PEG antibodies also can induce deposition of complement fragments onto the surface of PEGylated lipid-based nanoparticles and induce the release of fluid phase complement activation products.
The role of the different complement pathways activated by lipid-based nanoparticles was studied using deficient sera and/or inhibitory antibodies. We identified a major role for the classical complement pathway in the early activation events leading to the activation of C3. Our data also confirm the essential role of amplification of C3 activation by alternative pathway components in the lysis of liposomes.
Finally, the levels of pre-existing anti-PEG IgM antibodies in plasma of healthy donors correlated with the degree of complement activation (fixation and lysis) induced upon exposure to PEGylated liposomes and mRNA-LNPs.
Taken together, anti-PEG antibodies trigger complement activation by PEGylated lipid-based nanoparticles, which can potentially compromise their integrity, leading to premature drug release or cargo exposure to serum proteins.
Display omitted
•Pre-existing anti-PEG Abs in human serum induce activation of complement.•Classical pathway drives initial activation, amplification is crucial for lytic pathway.•Complement fragments deposit on the surface of immobilized PEGylated liposomes.•Complement activation triggered by anti-PEG Abs compromises lipid-based NP integrity.
Chemotherapy-induced peripheral neuropathy (CIPN), characterized by pain and numbness in hands and feet, is a common side effect of cancer treatment. In most patients, symptoms of CIPN subside after ...treatment completion. However, in a substantial subgroup, CIPN persists long into survivorship. Impairment in pain resolution pathways may explain persistent CIPN. We investigated the contribution of T cells and endogenous interleukin (IL)-10 to resolution of CIPN. Paclitaxel-induced mechanical allodynia was prolonged in T-cell-deficient (Rag1
) mice compared with wild-type (WT) mice. There were no differences between WT and Rag1
mice in severity of paclitaxel-induced mechanical allodynia. Adoptive transfer of either CD3
or CD8
, but not CD4
, T cells to Rag1
mice normalized resolution of CIPN. Paclitaxel treatment increased the number of T cells in lumbar dorsal root ganglia (DRG), where CD8
T cells were the major subset. Inhibition of endogenous IL-10 signaling by intrathecal injection of anti-IL-10 to WT mice or Rag1
mice reconstituted with CD8
T cells delayed recovery from paclitaxel-induced mechanical allodynia. Recovery was also delayed in IL-10 knock-out mice. Conversely, administration of exogenous IL-10 attenuated paclitaxel-induced allodynia. In vitro, IL-10 suppressed abnormal paclitaxel-induced spontaneous discharges in DRG neurons. Paclitaxel increased DRG IL-10 receptor expression and this effect requires CD8
T cells. In conclusion, we identified a novel mechanism for resolution of CIPN that requires CD8
T cells and endogenous IL-10. We propose that CD8
T cells increase DRG IL-10 receptor expression and that IL-10 suppresses the abnormal paclitaxel-induced spontaneous discharges by DRG neurons to promote recovery from CIPN.
Chemotherapy-induced peripheral neuropathy persists after completion of cancer treatment in a significant subset of patients, whereas others recover. Persistent neuropathy after completion of cancer treatment severely affects quality of life. We propose that understanding how neuropathy resolves will identify novel avenues for treatment. We identified a novel and critical role for CD8
T cells and for endogenous IL-10 in recovery from paclitaxel-induced neuropathy in mice. Enhancing the capacity of CD8
T cells to promote resolution or increasing IL-10 signaling are promising targets for novel interventions. Clinically, peripheral blood CD8
T-cell function and/or the capacity of individuals to produce IL-10 may represent biomarkers of risk for developing persistent peripheral neuropathy after completion of cancer treatment.
Episodic and recurrent local cutaneous or mucosal swelling are key features of angioedema. The vasoactive agents
histamine
and
bradykinin
are highly implicated as mediators of these swelling attacks. ...It is challenging to assess the contribution of
bradykinin
to the clinical expression of angioedema, as accurate biomarkers for the generation of this vasoactive peptide are still lacking. In this review, we will describe the mechanisms that are responsible for
bradykinin
production in hereditary angioedema (HAE) and the central role that the coagulation factor XII (FXII) plays in it. Evidently, several plasma parameters of coagulation change during attacks of HAE and may prove valuable biomarkers for disease activity. We propose that these changes are secondary to vascular leakage, rather than a direct consequence of FXII activation. Furthermore, biomarkers for fibrinolytic system activation (i.e.
plasminogen
activation) also change during attacks of HAE. These changes may reflect triggering of the
bradykinin-
forming mechanisms by
plasmin
. Finally, multiple lines of evidence suggest that neutrophil activation and mast-cell activation are functionally linked to
bradykinin
production. We put forward the paradigm that FXII functions as a ‘sensor molecule’ to detect conditions that require
bradykinin
release via crosstalk with cell-derived enzymes. Understanding the mechanisms that drive
bradykinin
generation may help to identify angioedema patients that have
bradykinin
-mediated disease and could benefit from a targeted treatment.
Hereditary angioedema (HAE) caused by a deficiency of functional C1-inhibitor (C1INH) becomes clinically manifest as attacks of angioedema. C1INH is the main inhibitor of the contact system. Poor ...control of a local activation process of this system at the site of the attack is believed to lead to the formation of bradykinin (BK), which increases local vasopermeability and mediates angioedema on interaction with BK receptor 2 on the endothelium. However, several observations in patients with HAE are difficult to explain from a pathogenic model claiming a local activation process at the site of the angioedema attack. Therefore we postulate an alternative model for angioedema attacks in patients with HAE, which assumes a systemic, fluid-phase activation of the contact system to generate BK and its breakdown products. Interaction of these peptides with endothelial receptors that are locally expressed in the affected tissues rather than with receptors constitutively expressed by the endothelium throughout the whole body explains that such a systemic activation process results in local manifestations of an attack. In particular, BK receptor 1, which is induced on the endothelium by inflammatory stimuli, such as kinins and cytokines, meets the specifications of the involved receptor. The pathogenic model discussed here also provides an explanation for why angioedema can occur at multiple sites during an attack and why HAE attacks respond well to modest increases of circulating C1INH activity levels because inhibition of fluid-phase Factor XIIa and kallikrein requires lower C1INH levels than inhibition of activator-bound factors.
New therapeutic approaches to resolve persistent pain are highly needed. We tested the hypothesis that manipulation of cytokine receptors on sensory neurons by clustering regulatory cytokine receptor ...pairs with a fusion protein of interleukin (IL)-4 and IL-10 (IL4-10 FP) would redirect signaling pathways to optimally boost pain-resolution pathways. We demonstrate that a population of mouse sensory neurons express both receptors for the regulatory cytokines IL-4 and IL-10. This population increases during persistent inflammatory pain. Triggering these receptors with IL4-10 FP has unheralded biological effects, because it resolves inflammatory pain in both male and female mice. Knockdown of both IL4 and IL10 receptors in sensory neurons in vivo ablated the IL4-10 FP-mediated inhibition of inflammatory pain. Knockdown of either one of the receptors prevented the analgesic gain-of-function of IL4-10 FP. In vitro, IL4-10 FP inhibited inflammatory mediator-induced neuronal sensitization more effectively than the combination of cytokines, confirming its superior activity. The IL4-10 FP, contrary to the combination of IL-4 and IL-10, promoted clustering of IL-4 and IL-10 receptors in sensory neurons, leading to unique signaling, that is exemplified by activation of shifts in the cellular kinome and transcriptome. Interrogation of the potentially involved signal pathways led us to identify JAK1 as a key downstream signaling element that mediates the superior analgesic effects of IL4-10 FP. Thus, IL4-10 FP constitutes an immune-biologic that clusters regulatory cytokine receptors in sensory neurons to transduce unique signaling pathways required for full resolution of persistent inflammatory pain.
Hereditary angioedema (HAE), a rare but life-threatening condition, manifests as acute attacks of facial, laryngeal, genital, or peripheral swelling or abdominal pain secondary to intra-abdominal ...edema. Resulting from mutations affecting C1 esterase inhibitor (C1-INH), inhibitor of the first complement system component, attacks are not histamine-mediated and do not respond to antihistamines or corticosteroids. Low awareness and resemblance to other disorders often delay diagnosis; despite availability of C1-INH replacement in some countries, no approved, safe acute attack therapy exists in the United States. The biennial C1 Esterase Inhibitor Deficiency Workshops resulted from a European initiative for better knowledge and treatment of HAE and related diseases. This supplement contains work presented at the third workshop and expanded content toward a definitive picture of angioedema in the absence of allergy. Most notably, it includes cumulative genetic investigations; multinational laboratory diagnosis recommendations; current pathogenesis hypotheses; suggested prophylaxis and acute attack treatment, including home treatment; future treatment options; and analysis of patient subpopulations, including pediatric patients and patients whose angioedema worsened during pregnancy or hormone administration. Causes and management of acquired angioedema and a new type of angioedema with normal C1-INH are also discussed. Collaborative patient and physician efforts, crucial in rare diseases, are emphasized. This supplement seeks to raise awareness and aid diagnosis of HAE, optimize treatment for all patients, and provide a platform for further research in this rare, partially understood disorder.
Background Hereditary angioedema (HAE) results from a genetic deficiency of C1-inhibitor. Two similar independent, randomized, saline controlled, double-blind studies were conducted to evaluate the ...efficacy and safety of recombinant human C1-inhibitor (rhC1INH) as a treatment of acute angioedema attacks in patients with HAE. Objective Analysis of pooled study results. Methods Patients with an eligible attack were randomized to a single intravenous dose of rhC1INH or saline. Efficacy was assessed by using patient-reported visual analog scale outcomes, and safety was assessed by using adverse events and immunogenicity of rhC1INH. Results rhC1INH at 100 (n = 29) and 50 (n = 12) U/kg body weight resulted in a significant reduction for both the primary endpoint time to the beginning of relief of symptoms compared with saline (n = 29): median, 66 (95% CI, 61-122) minutes, 122 (72-136) minutes, and 495 (245-520) minutes, P < .001 and P = .013, respectively; and for the secondary endpoint time to minimal symptoms, median, 266 (242-490) minutes, 247 (243-484) minutes, and 1210 (970-1500) minutes, P < .001 and P = .001, respectively. Therapeutic failure occurred in 59% (17/29) of the saline group compared with 0% (0/12) of the 50 U/kg group and 10% (3/29) of the 100 U/kg group. Treatment-emergent adverse events were unremarkable and tended to be reported more frequently in the saline group. No postexposure antibody responses against rhC1INH or host-related impurities were observed. Conclusion Administration of rhC1INH at 100 or 50 U/kg was highly effective as a treatment of acute attacks in patients with HAE and appeared to be safe and well tolerated.
Disseminated intravascular coagulation is a frequent complication of sepsis. Coagulation activation, inhibition of fibrinolysis, and consumption of coagulation inhibitors lead to a procoagulant state ...resulting in inadequate fibrin removal and fibrin deposition in the microvasculature. As a consequence, microvascular thrombosis contributes to promotion of organ dysfunction. Recently, three randomized, double-blind, placebo-controlled trials investigated the efficacy of antithrombin, activated protein C (APC), and tissue factor pathway inhibitor, respectively, in sepsis patients. A significant reduction in mortality was demonstrated in the APC trial. In this article, we first discuss the physiology of coagulation and fibrinolysis activation. Then, the pathophysiology of coagulation activation, consumption of coagulation inhibitors, and the inhibition of fibrinolysis leading to a procoagulant state are described in more detail. Moreover, therapeutic concepts as well as the three randomized, double-blind, placebo-controlled studies are discussed.
Serine proteases form a large family of protein-cleaving enzymes that play an essential role in processes like blood coagulation, apoptosis and inflammation. Immune cells express a wide variety of ...serine proteases such as granzymes in cytotoxic lymphocytes, neutrophil elastase, cathepsin G and proteinase 3 in neutrophils and chymase and tryptase in mast cells. Regulation of proteolysis induced by these serine proteases is essential to prevent self-induced damage. Hence, there are specialized serine protease inhibitors, serpins, which are broadly distributed. Here, we discuss the function of human serine proteases in inflammation, apoptosis and tissue remodeling. Furthermore, we address their impact on development and progression of immune mediated-diseases. Understanding the mode of action of serine proteases will help to unravel molecular processes involved in immunological disorders and will facilitate the identification of new therapeutic targets.
PDF
