Platelet Hyperactivity in TNFSF14/LIGHT Knockout Mouse Model of Impaired Healing

Signaling Pathways Associated with Chronic Wound Progression: A Systems Biology Approach

Previously we have shown that several oxidative stress-driven pathways in cutaneous chronic wounds are dysregulated in the first 48 h post-wounding. Here, we performed an RNASeq analysis of tissues collected up to day 20 after wounding, when we have determined full chronicity is established. Weighted Gene Correlation Network Analysis was performed in R segregating the genes into 14 modules. Genes in the modules significantly correlated (p < 0.05) to early and full chronicity were used for pathway analysis using pathfindR. In early chronicity, we observed enrichment of several pathways. Dysregulation of Ephrin/Eph signaling leads to growth cone collapse and impairs neuronal regeneration. Adra2b and Adra2a overexpression in early and full chronicity, respectively, decreased cAMP production and impaired re-epithelialization and granulation tissue formation. Several pathways involving a Smooth-muscle-actin (Acta1) were also enriched with Acta1 overexpression contributing to impaired angiogenesis. During full chronicity, the ‘JAK-STAT’ pathway was suppressed undermining host defenses against infection. Wnt signaling was also suppressed, impairing re-epithelialization and granulation tissue formation. Biomarkers of cancer such as overexpression of SDC1 and constitutive activation of ErbB2/HER2 were also identified. In conclusion, we show that during progression to full chronicity, numerous signaling pathways are dysregulated, including some related to carcinogenesis, suggesting that chronic wounds behave much like cancer. Experimental verification in vivo could identify candidates for treatment of chronic wounds.

LIGHT (TNFSF14) inhibits glucose uptake of adipocytes by downregulating GLUT4 expression via AKT signaling pathway

Glucose homeostasis of adipocytes could be regulated by immune-adipose crosstalk. In order to investigate the effects of Lymphotoxin-like inducible protein that competes with glycoprotein D for herpesvirus entry on T cells (LIGHT) on glucose metabolism, we performed the present study. Our results showed that LIGHT deficiency improved glucose tolerance and enhanced glucose consumption of inguinal white adipose tissue (iWAT) under high fat diet. Consistently, Light overexpression could inhibit glucose uptake during the process of white adipogenesis. Mechanistically, LIGHT interacted with lymphotoxin-β receptor (LTβR) to attenuate AKT pathway leading to downregulation of glucose transporter-4 (GLUT4) expression, which resulted in glucose uptake inhibition. In summary, our findings revealed LIGHT-LTβR-AKT-GLUT4 axis as a regulator of glucose uptake in adipose tissue, which suggested the pivotal role of LIGHT in maintaining glucose homeostasis.

TNFSF14-Derived Molecules as a Novel Treatment for Obesity and Type 2 Diabetes

Obesity is one of the most prevalent metabolic diseases in the Western world and correlates directly with glucose intolerance and insulin resistance, often culminating in Type 2 Diabetes (T2D). Importantly, our team has recently shown that the TNF superfamily (TNFSF) member protein, TNFSF14, has been reported to protect against high fat diet induced obesity and pre-diabetes. We hypothesized that mimics of TNFSF14 may therefore be valuable as anti-diabetic agents. In this study, we use in silico approaches to identify key regions of TNFSF14 responsible for binding to the Herpes virus entry mediator and Lymphotoxin β receptor. In vitro evaluation of a selection of optimised peptides identified six potentially therapeutic TNFSF14 peptides. We report that these peptides increased insulin and fatty acid oxidation signalling in skeletal muscle cells. We then selected one of these promising peptides to determine the efficacy to promote metabolic benefits in vivo. Importantly, the TNFSF14 peptide 7 reduced high fat diet-induced glucose intolerance, insulin resistance and hyperinsulinemia in a mouse model of obesity. In addition, we highlight that the TNFSF14 peptide 7 resulted in a marked reduction in liver steatosis and a concomitant increase in phospho-AMPK signalling. We conclude that TNFSF14-derived molecules positively regulate glucose homeostasis and lipid metabolism and may therefore open a completely novel therapeutic pathway for treating obesity and T2D.

Increased level of LIGHT/TNFSF14 is associated with survival in aneurysmal subarachnoid hemorrhage

OBJECTIVES

Multiple cytokines have been implicated in aneurysmal subarachnoid hemorrhage (aSAH), but tumor necrosis factor superfamily 14 (LIGHT/TNFSF14) and oncostatin-M (OSM) have not been previously explored.

AIMS OF THE STUDY

The primary objective of this study was to examine the relationship between TNFSF14 and OSM levels and survival. Our secondary goal was to investigate a potential association between these markers and the incidence of delayed cerebral ischemia (DCI).

MATERIALS & METHODS

We consecutively recruited 60 patients with a clinical diagnosis of aSAH. LIGHT/TNFSF14 and OSM serum concentrations were determined by ELISA. The primary endpoint was survival at Day 30, while development of DCI was assessed as secondary outcome.

RESULTS

Patients had significantly higher levels of both markers than the control group (median of LIGHT: 18.1 pg/ml vs. 7 pg/ml; p = 0.01; median of OSM: 10.3 pg/ml vs. 2.8 pg/ml, p < 0.001). Significantly lower serum level of LIGHT/TNFSF14 was found in nonsurviving patients (n = 9) compared with survivors (n = 51; p = 0.011). Based on ROC analysis, serum LIGHT/TNFSF14 with a cutoff value of >7.95 pg/ml predicted 30-day survival with a sensitivity of 71% and specificity of 78% (Area: 0.763; 95% CI: 0.604-0.921, p = 0.013). In addition, it was also a predictor of DCI with a sensitivity of 72.7% and a specificity of 62.5% (AUC: 0.702; 95% CI: 0.555-0.849, p = 0.018). Based on binary logistic regression analysis, LIGHT/TNFSF14 was found to be independently associated with 30-day mortality, but not with DCI.

CONCLUSION

In this cohort, a higher serum level of LIGHT/TNFSF14 was associated with increased survival of patients with aSAH.

Deficiency of platelet adhesion molecule CD226 causes megakaryocyte development and platelet hyperactivity

This study used constitutive CD226 gene knockout (KO) mice as a model to investigate the functions and mechanisms of CD226 in megakaryocyte (MK) maturation and platelet activation. Although CD226 deficiency did not cause MK polyploidization or platelet granule abnormalities, increased MK counts were detected in the femora bone marrow (BM) and spleen of CD226 KO mice. Particularly, CD226 KO mice have a more extensive membrane system in MKs and platelets than wild-type (WT) mice. We also demonstrated that CD226 KO mice displayed increased platelet counts, shortened bleeding time, and enhanced platelet aggregation. CD226 KO platelets had an increased mature platelet ratio compared to the control platelets. In addition, the observed reduction in bleeding time may be due to decreased nitric oxide (NO) production in the platelets. Platelet-specific CD226-deficient mice showed similar increased MK counts, shortened bleeding time, enhanced platelet aggregation, and decreased NO production in platelets. Furthermore, we performed middle cerebral artery occlusion-reperfusion surgery on WT and CD226 KO mice to explore the potential effect of CD226 on acute ischemia-reperfusion injury; the results revealed that CD226 deficiency led to significantly increased infarct area. Thus, CD226 is a promising candidate for the treatment of thrombotic disorders.

Wound-Healing Markers Revealed by Proximity Extension Assay in Tears of Patients following Glaucoma Surgery

Tears are a constantly available and highly valuable body fluid collectable by non-invasive techniques. Although it can give information on ocular status and be used for follow-ups, tear analysis is challenging due to the low amount of sample that is available. Proximity extension assay (PEA) allows for a sensitive and scalable analysis of multiple proteins in a single run from a one-µL sample, so we applied this technique and examined the amount of 184 proteins in tears collected at different time points after trabeculectomy. The success rate of this surgical intervention highly depends on proper wound healing; therefore, information on the process is indispensable. We observed significantly higher levels of IL-6 and MMP1 at the early time points (day one, two, and four) following trabeculectomy, and the protein amounts went back to the level observed before the surgery three months after the intervention. Patients with or without complications were tested, and proteins that have roles in the immune response and wound healing could be observed with altered frequency and amounts in the cases of patients with complications. Our results highlight the importance of inflammation in wound-healing complications, and at the same time, indicate the utility of PEA in tear analysis.

Role of IκB kinase β in regulating the remodeling of the CARMA1-Bcl10-MALT1 complex

The current work investigates the notion that inducible clustering of signaling mediators of the IKK pathway is important for platelet activation. Thus, while the CARMA1, Bcl10, and MALT1 (CBM) complex is essential for triggering IKK/NF-κB activation upon platelet stimulation, the signals that elicit its formation and downstream effector activation remain elusive. We demonstrate herein that IKKβ is involved in membrane fusion, and serves as a critical protein kinase required for initial formation and the regulation of the CARMA1/MALT1/Bcl10/CBM complex in platelets. We also show that IKKβ regulates these processes via modulation of phosphorylation of Bcl10 and IKKγ polyubiquitination. Collectively, our data demonstrate that IKKβ regulates membrane fusion and the remodeling of the CBM complex formation.