Chemical Antagonists of Plasminogen Activator Inhibitor-1: Mechanisms of Action and Therapeutic Potential in Vascular Disease

Serp-1 Promotes Corneal Wound Healing by Facilitating Re-epithelialization and Inhibiting Fibrosis and Angiogenesis

Purpose: Chemical corneal injuries carry a high morbidity and commonly lead to visual impairment. Here, we investigate the role of Serp-1, a serine protease inhibitor, in corneal wound healing.

Methods: An alkaline-induced corneal injury was induced in 14 mice. Following injury, five mice received daily topical saline application while nine mice received Serp-1 100 μL topically combined with a daily subcutaneous injection of 100 ng/gram body weight of Serp-1. Corneal damage was monitored daily through fluorescein staining and imaging. Cross sectional corneal H&E staining were obtained. CD31 was used as marker for neovascularization.

Results: Serp-1 facilitates corneal wound healing by reducing fibrosis and neovascularization while mitigating inflammatory cell infiltration with no noticeable harm related to its application.

Conclusions: Serp-1 effectively mitigates inflammation, decreases fibrosis, and reduce neovascularization in a murine model of corneal injury without affecting other organs.

Translational Relavence: Our study provides preclinical data for topical application of Serp-1 to treat corneal wounds.

Prenatal Exposure to Electronic-Cigarette Aerosols Leads to Sex-Dependent Pulmonary Extracellular-Matrix Remodeling and Myogenesis in Offspring Mice

Electronic-cigarette (e-cig) vaping is a serious concern, as many pregnant women who vape consider it safe. However, little is known about the harmful effects of prenatal e-cig exposure on adult offspring, especially on extracellular-matrix (ECM) deposition and myogenesis in the lungs of offspring. We evaluated the biochemical and molecular implications of maternal exposure during pregnancy to e-cig aerosols on the adult offspring of both sexes, with a particular focus on pulmonary ECM remodeling and myogenesis. Pregnant CD-1 mice were exposed to e-cig aerosols with or without nicotine, throughout gestation, and lungs were collected from adult male and female offspring. Compared with the air-exposed control group, female mice exposed to e-cig aerosols, with or without nicotine, demonstrated increased lung protein abundance of LEF-1 (lymphoid enhancer-binding factor 1), fibronectin, and E-cadherin, whereas altered E-cadherin and PPARγ (peroxisome proliferator-activated receptor γ) levels were observed only in males exposed to e-cig aerosols with nicotine. Moreover, lipogenic and myogenic mRNAs were dysregulated in adult offspring in a sex-dependent manner. PAI-1 (plasminogen activator inhibitor-1), one of the ECM regulators, was significantly increased in females exposed prenatally to e-cig aerosols with nicotine and in males exposed to e-cig aerosols compared with control animals exposed to air. MMP9 (matrix metalloproteinase 9), a downstream target of PAI-1, was downregulated in both sexes exposed to e-cig aerosols with nicotine. No differences in lung histology were observed among any of the treatment groups. Overall, adult mice exposed prenatally to e-cig aerosols could be predisposed to developing pulmonary disease later in life. Thus, these findings suggest that vaping during pregnancy is unsafe and increases the propensity for later-life interstitial lung diseases.

Recognition of Plasminogen Activator Inhibitor Type 1 as the Primary Regulator of Fibrinolysis

The fibrinolytic system consists of a balance between rates of plasminogen activation and fibrin degradation, both of which are finely regulated by spatio-temporal mechanisms. Three distinct inhibitors of the fibrinolytic system that differently regulate these two steps are plasminogen activator inhibitor type-1 (PAI-1), α2-antiplasmin, and thrombin activatable fibrinolysis inhibitor (TAFI). In this review, we focus on the mechanisms by which PAI-1 governs total fibrinolytic activity to provide its essential role in many hemostatic disorders, including fibrinolytic shutdown after trauma. PAI-1 is a member of the serine protease inhibitor (SERPIN) superfamily and inhibits the protease activities of plasminogen activators (PAs) by forming complexes with PAs, thereby regulating fibrinolysis. The major PA in the vasculature is tissue-type PA (tPA) which is secreted from vascular endothelial cells (VECs) as an active enzyme and is retained on the surface of VECs. PAI-1, existing in molar excess to tPA in plasma, regulates the amount of free active tPA in plasma and on the surface of VECs by forming a tPA-PAI-1 complex. Thus, high plasma levels of PAI-1 are directly related to attenuated fibrinolysis and increased risk for thrombosis. Since plasma PAI-1 levels are highly elevated under a variety of pathological conditions, including infection and inflammation, the fibrinolytic potential in plasma and on VECs is readily suppressed to induce fibrinolytic shutdown. A congenital deficiency of PAI-1 in humans, in turn, leads to life-threatening bleeding. These considerations support the contention that PAI-1 is the primary regulator of the initial step of fibrinolysis and governs total fibrinolytic activity.

Towards frailty biomarkers: Candidates from genes and pathways regulated in aging and age-related diseases

OBJECTIVE

Use of the frailty index to measure an accumulation of deficits has been proven a valuable method for identifying elderly people at risk for increased vulnerability, disease, injury, and mortality. However, complementary molecular frailty biomarkers or ideally biomarker panels have not yet been identified. We conducted a systematic search to identify biomarker candidates for a frailty biomarker panel.

METHODS

Gene expression databases were searched (http://genomics.senescence.info/genes including GenAge, AnAge, LongevityMap, CellAge, DrugAge, Digital Aging Atlas) to identify genes regulated in aging, longevity, and age-related diseases with a focus on secreted factors or molecules detectable in body fluids as potential frailty biomarkers. Factors broadly expressed, related to several "hallmark of aging" pathways as well as used or predicted as biomarkers in other disease settings, particularly age-related pathologies, were identified. This set of biomarkers was further expanded according to the expertise and experience of the authors. In the next step, biomarkers were assigned to six "hallmark of aging" pathways, namely (1) inflammation, (2) mitochondria and apoptosis, (3) calcium homeostasis, (4) fibrosis, (5) NMJ (neuromuscular junction) and neurons, (6) cytoskeleton and hormones, or (7) other principles and an extensive literature search was performed for each candidate to explore their potential and priority as frailty biomarkers.

RESULTS

A total of 44 markers were evaluated in the seven categories listed above, and 19 were awarded a high priority score, 22 identified as medium priority and three were low priority. In each category high and medium priority markers were identified.

CONCLUSION

Biomarker panels for frailty would be of high value and better than single markers. Based on our search we would propose a core panel of frailty biomarkers consisting of (1) CXCL10 (C-X-C motif chemokine ligand 10), IL-6 (interleukin 6), CX3CL1 (C-X3-C motif chemokine ligand 1), (2) GDF15 (growth differentiation factor 15), FNDC5 (fibronectin type III domain containing 5), vimentin (VIM), (3) regucalcin (RGN/SMP30), calreticulin, (4) PLAU (plasminogen activator, urokinase), AGT (angiotensinogen), (5) BDNF (brain derived neurotrophic factor), progranulin (PGRN), (6) α-klotho (KL), FGF23 (fibroblast growth factor 23), FGF21, leptin (LEP), (7) miRNA (micro Ribonucleic acid) panel (to be further defined), AHCY (adenosylhomocysteinase) and KRT18 (keratin 18). An expanded panel would also include (1) pentraxin (PTX3), sVCAM/ICAM (soluble vascular cell adhesion molecule 1/Intercellular adhesion molecule 1), defensin α, (2) APP (amyloid beta precursor protein), LDH (lactate dehydrogenase), (3) S100B (S100 calcium binding protein B), (4) TGFβ (transforming growth factor beta), PAI-1 (plasminogen activator inhibitor 1), TGM2 (transglutaminase 2), (5) sRAGE (soluble receptor for advanced glycosylation end products), HMGB1 (high mobility group box 1), C3/C1Q (complement factor 3/1Q), ST2 (Interleukin 1 receptor like 1), agrin (AGRN), (6) IGF-1 (insulin-like growth factor 1), resistin (RETN), adiponectin (ADIPOQ), ghrelin (GHRL), growth hormone (GH), (7) microparticle panel (to be further defined), GpnmB (glycoprotein nonmetastatic melanoma protein B) and lactoferrin (LTF). We believe that these predicted panels need to be experimentally explored in animal models and frail cohorts in order to ascertain their diagnostic, prognostic and therapeutic potential.

uPA/uPAR and SERPINE1 in head and neck cancer: role in tumor resistance, metastasis, prognosis and therapy

There is strong evidence supporting the role of the plasminogen activator system in head and neck squamous cell carcinoma (HNSCC), particularly of its uPA (urokinase plasminogen activator) / uPAR (urokinase plasminogen activator receptor) and SERPINE1 components. Overexpression of uPA/uPAR and SERPINE1 enhances tumor cell migration and invasion and plays a key role in metastasis development, conferring poor prognosis. The apparent paradox of uPA/uPAR and its inhibitor SERPINE1 producing similar effects is solved by the identification of SERPINE1 activated signaling pathways independent of uPA inhibition. Both uPA/uPAR and SERPINE1 are directly linked to the induction of epithelial-to-mesenchymal transition, the acquisition of stem cell properties and resistance to antitumor agents. The aim of this review is to provide insight on the deregulation of these proteins in all these processes.

We also summarize their potential value as prognostic biomarkers or potential drug targets in HNSCC patients. Concomitant overexpression of uPA/uPAR and SERPINE1 is associated with a higher risk of metastasis and could be used to identify patients that would benefit from an adjuvant treatment. In the future, the specific inhibitors of uPA/uPAR and SERPINE1, which are still under development, could be used to design new therapeutic strategies in HNSCCs.

SERPINE1 rs1799768 polymorphism contributes to sepsis risk and mortality

INTRODUCTION

The present meta-analysis aimed to investigate whether there is an association between SERPINE1 rs1799768 polymorphism and sepsis risk and mortality.

MATERIALS AND METHODS

Published reports were searched in PubMed, PubMed Central, Gene, PubChem and Google Scholar. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were assessed in a random-effects model.

RESULTS

The results of the overall meta-analysis indicated that an increased sepsis risk was evidently associated with SERPINE1 rs1799768 polymorphism (OR = 1.30; 95% CI 1.08-1.56; p = 0.006). When studies were stratified by ethnicity, no significant association was observed between SERPINE1 rs1799768 polymorphism and sepsis risk in the Asian group. As for the Caucasian population, overall OR was 1.24 (95% CI 1.02-1.51; p = 0.03). The results of the overall meta-analysis indicated that an increased sepsis mortality risk was evidently associated with SERPINE1 rs1799768 polymorphism (OR = 1.73; 95% CI 1.31-2.28; p < 0.0001). When studies were stratified by ethnicity, significant association was observed between SERPINE1 rs1799768 polymorphism and sepsis risk mortality in the Asian group and the Caucasian population.

CONCLUSIONS

In conclusion, the meta-analysis suggests that there are significant associations between SERPINE1 rs1799768 polymorphism and risk of sepsis and sepsis mortality.