Analysis of N1‐acetyl‐N2‐formyl‐5‐methoxykynuramine/N1‐acetyl‐5‐methoxy‐kynuramine formation from melatonin in mice

Abstract: The interactions of melatonin, a potent endogenous antioxidant, with reactive oxygen species generate several products that include N¹‐acetyl‐N²‐formyl‐5‐methoxykynuramine (AFMK) and N¹‐acetyl‐5‐methoxy‐kynuramine (AMK). The physiological or pathological significance of AFMK/AMK formation during the process of melatonin metabolism in mammals has not been clarified. Using a metabolomic approach in the current study, the AFMK/AMK pathway was thoroughly investigated both in mice and humans. Unexpectedly, AFMK and AMK were not identified in the urine of humans nor in the urine, feces or tissues (including liver, brain, and eyes) in mice under the current experimental conditions. Metabolomic analysis did identify novel metabolites of AMK, i.e. hydroxy‐AMK and glucuronide‐conjugated hydroxy‐AMK. These two newly identified metabolites were, however, not found in the urine of humans. In addition, oxidative stress induced by acetaminophen in the mouse model did not boost AFMK/AMK formation. These data suggest that AFMK/AMK formation is not a significant pathway of melatonin disposition in mice, even under conditions of oxidative stress.     

Fulminant type 1 diabetes mellitus with anti‐programmed cell death‐1 therapy

Anti‐programmed cell death‐1 (PD‐1) antibodies are regarded as a risk factor for insulin‐dependent diabetes mellitus as a side‐effect. While a small number of cases have been reported, evidence remains limited. This is the first report of an Asian patient developing insulin‐dependent diabetes during anti‐PD‐1 therapy. A 55‐year‐old euglycemic woman receiving nivolumab for malignant melanoma showed abrupt onset of ketonuria, and elevated levels of plasma glucose (580 mg/dL) and hemoglobin A1c (7.0%). Over the next 2 weeks, serum C‐peptide levels fell below the limit of detection. Islet autoantibodies were negative, and the patient showed a human leukocyte antigen haplotype associated with type 1 diabetes. Anti‐PD‐1 therapy can cause rapid onset of insulin‐dependent diabetes, possibly because of inappropriate activation of T cells. Human leukocyte antigen haplotypes might be related to the onset of this disease. Physicians should be aware of this serious adverse event and carry out routine blood glucose testing during anti‐PD‐1 therapy.     

JNK‐1 deficiency limits macrophage‐mediated antigen‐induced arthritis

Objective

To elucidate the nonredundant roles of JNK‐1 and JNK‐2 in antigen‐induced arthritis (AIA).

Methods

Mice that were genetically disrupted in Jnk1 or Jnk2 were primed by injection of methylated bovine serum albumin (mBSA) in Freund's complete adjuvant and then challenged on day 21 by intraarticular injection of mBSA into the right knee. Bone marrow chimeras were generated and similarly treated. Joints were harvested and prepared for histologic assessment. T cell responses were verified by cytokine and proliferation responses, and relative immunoglobulin responses were measured by enzyme‐linked immunosorbent assay. Cytokine messenger RNA expression levels were measured by quantitative polymerase chain reaction analysis. Thioglycollate‐elicited and zymosan A–elicited macrophage recruitment was tested in vivo, and cell migration was tested in vitro. The peptide inhibitor D‐JNKi was injected daily starting 4 days after intraarticular injection of mBSA into wild‐type (WT) mice, and inflammation was scored histologically.

Results

JNK‐1–deficient, but not JNK‐2–deficient, mice had a reduction in inflammatory cell infiltration and joint damage. This effect was primarily restricted to hematopoietic cells, but B and T cell responses were preserved in mBSA‐injected mice. JNK‐1–deficient macrophages produced cytokines and chemokines at a level comparable to that in their WT counterparts. However, macrophage migration was impaired in vivo and in vitro. Targeting JNK with the peptide inhibitor D‐JNKi dramatically reduced inflammation and joint destruction in WT mice.

Conclusion

AIA is dependent on JNK‐1, but not JNK‐2. JNK‐1 is a promising molecular target for reducing autoimmune inflammation, since its inhibition impairs macrophage migration.

     

Estimation of monocyte‐chemoattractantprotein‐1 (Mcp‐1) level in patients with lupus nephritis

Aim: To evaluate the use of non‐invasive estimation of CP‐1 in urine as a good indicator for lupus nephritis activity. Methods: The study was conducted on 30 patients with systemic lupus erythematosus (SLE) (group I): 15 of these patients were selected without renal involvement (group I [A]), and the other 15 were selected with evidence of renal involvement (group I [B]). Further 10 age‐ and sex‐matched healthy subjects were taken as a control group (group II). The SLE disease activity index (SLEDAI) was applied. Laboratory investigations done for the studied group of patients included: renal function tests (antinuclear antibody) titer, (anti‐double‐stranded DNA) titer, and monocyte chemotactic protein 1 (MCP‐1) level in serum and urine samples. Results: Serum MCP‐1 was significantly higher in SLE patients with nephritis than in the control group, while no significant difference was found between SLE patients without nephritis and the control group. Urinary MCP‐1 in patients with active lupus nephritis (LN) were significantly higher than both patients with inactive LN and control the group. Urinary MCP‐1 in SLE patients with nephritis was significantly higher than both group I (A) and group II. Urinary MCP‐1 correlated positively with proteinuria, and negatively with creatinine clearance and hemoglobin; thus, urinary MCP‐1 correlates with the severity of nephritis. Conclusion: Urinary and not serum MCP‐1 is a useful invasive technique for the assessment of renal disease activity in patients with LN.     

Review of head‐to‐head comparisons of glucagon‐like peptide‐1 receptor agonists

Currently, six glucagon‐like peptide‐1 receptor agonists (GLP‐1RAs) are approved for treating type 2 diabetes. These fall into two classes based on their receptor activation: short‐acting exenatide twice daily and lixisenatide once daily; and longer‐acting liraglutide once daily, exenatide once weekly, albiglutide once weekly and dulaglutide once weekly. The phase III trial of a seventh GLP‐1RA, taspoglutide once weekly, was stopped because of unacceptable adverse events (AEs). Nine phase III head‐to‐head trials and one large phase II study have compared the efficacy and safety of these seven GLP‐1RAs. All trials were associated with notable reductions in glycated haemoglobin (HbA1c) levels, although liraglutide led to greater decreases than exenatide formulations and albiglutide, and HbA1c reductions did not differ between liraglutide and dulaglutide. As the short‐acting GLP‐1RAs delay gastric emptying, they have greater effects on postprandial glucose levels than the longer‐acting agents, whereas the longer‐acting compounds reduced plasma glucose throughout the 24‐h period studied. Liraglutide was associated with weight reductions similar to those with exenatide twice daily but greater than those with exenatide once weekly, albiglutide and dulaglutide. The most frequently observed AEs with GLP‐1RAs were gastrointestinal disorders, particularly nausea, vomiting and diarrhoea. Nauseaoccurred less frequently, however, with exenatide once weekly and albiglutide than exenatide twice daily and liraglutide. Both exenatide formulations and albiglutide may be associated with higher incidences of injection‐site reactions than liraglutide and dulaglutide. GLP‐1RA use in clinical practice should be customized for individual patients, based on clinical profile and patient preference. Ongoing assessments of novel GLP‐1RAs and delivery methods may further expand future treatment options.     

Effect of ICAM‐1 and LFA‐1 in hyperleukocytic acute myeloid leukaemia

Acute hyperleukocytic leukemia [AHL; WBC count >100 × 10⁹/l] is associated with a life‐threatening complication. The mechanisms of hyperleukocytosis in acute myeloid leukaemia (AML) remain unclear. However, the interaction of intercellular adhesion molecule‐1 (ICAM‐1) and lymphocyte function‐associated antigen‐1 (LFA‐1) plays an important role in the adhesion and migration of normal leukocytes and AML cells. Therefore, effects of ICAM‐1 and LFA‐1 were studied in hyperleukocytic AML. The adhesion of hyperleukocytic AML blasts and human umbilical vein endothelial cells (HUVECs) was significantly increased compared with that of blasts from non‐hyperleukocytic AML (WBC < 100 × 10⁹/l). The adhesion of normal neutrophils and HUVECs treated with hyperleukocytic AML blast supernatant was increased significantly. Finally, we determined the ICAM‐1 on the surface of HUVECs treated with the supernatant of hyperleukocytic AML blasts and LFA‐1 on hyperleukocytic AML blasts by flow cytometry. It showed that the ICAM‐1 expression on the surface of the HUVECs treated with hyperleukocytic AML blast supernatant for 24 h could be increased, and the expression of LFA‐1 on hyperleukocytic AML was also increased significantly. Our data show that hyperleukocytic AML blasts stimulate the endothelium to secrete more ICAM‐1 and promote their own adhesion to vascular endothelium, suggesting that ICAM‐1 and LFA‐1 may have a role in hyperleukocytic AML.     

PD‐1/PD‐L1 pathway and T‐cell exhaustion in chronic hepatitis virus infection

Summary. Dysfunctional virus‐specific T cells are a hallmark of many chronic viral infections. Recent studies have implicated the inhibitory PD‐1/PD‐L1 pathway with the functional impairment of T cells. In this respect, we will review the latest research on PD‐1/PD‐L1 pathway and T‐cell exhaustion in the context of human chronic hepatitis B and C virus infections. We will also discuss the therapeutic potential of PD‐1 blockade and how it may be enhanced through the modulation of other co‐stimulatory/inhibitory pathways.     

Targeting anti‐beta‐1‐adrenergic receptor antibodies for dilated cardiomyopathy

Anti‐beta‐1‐adrenergic receptor antibodies (anti‐β₁AR Abs) have long been implicated in the pathogenesis of dilated cardiomyopathy (DCM). It is believed that these autoantibodies bind to and constitutively stimulate the β₁AR to promote pathological cardiac remodelling and β₁AR desensitization and downregulation. The prevalence of anti‐β₁AR Abs in patients with DCM ranges from 26% to 60%, and the presence of these autoantibodies correlates with a poor prognosis. Several small studies have shown improvements in functional status, haemodynamics, and biomarkers of heart failure upon removal or neutralization of these antibodies from the sera of affected patients. Traditionally, removal of anti‐β₁AR Abs required immunoadsorption therapy with apheresis columns directed against human immunoglobulins (Igs) and subsequent i.v. Ig infusion, thereby essentially performing a plasma exchange transfusion. However, recent advances have allowed the development of small peptides and nucleotide sequences that specifically target and neutralize anti‐β₁AR Abs, providing a hopeful avenue for future drug development to treat DCM. Herein, we briefly review the clinical literature of therapy directed against anti‐β₁AR Abs and highlight the opportunity for further research and development in this area.