Serine protease inhibitor A3 in atherosclerosis and aneurysm disease

Diagnostic and therapeutic value of human serpin family proteins

SERPIN (serine proteinase inhibitors) is an acronym for the superfamily of structurally similar proteins found in animals, plants, bacteria, viruses, and archaea. Over 1500 SERPINs are known in nature, while only 37 SERPINs are found in humans, which participate in inflammation, coagulation, angiogenesis, cell viability, and other pathophysiological processes. Both qualitative or quantitative deficiencies or overexpression and/or abnormal accumulation of SERPIN can lead to diseases commonly referred to as "serpinopathies". Hence, strategies involving SERPIN supplementation, elimination, or correction are utilized and/or under consideration. In this review, we discuss relationships between certain SERPINs and diseases as well as putative strategies for the clinical explorations of SERPINs.

Role of Serine Protease Inhibitors A1 and A3 in Ocular Pathologies

Serine protease inhibitors A1 (SerpinA1) and A3 (SerpinA3) are important members of the serpin family, playing crucial roles in the regulation of serine proteases and influencing various physiological processes. SerpinA1, also known as α-1-antitrypsin, is a versatile glycoprotein predominantly synthesized in the liver, with additional production in inflammatory and epithelial cell types. It exhibits multifaceted functions, including immune modulation, complement activation regulation, and inhibition of endothelial cell apoptosis. SerpinA3, also known as α-1-antichymotrypsin, is expressed both extracellularly and intracellularly in various tissues, particularly in the retina, kidney, liver, and pancreas. It exerts anti-inflammatory, anti-angiogenic, antioxidant, and antifibrotic activities. Both SerpinA1 and SerpinA3 have been implicated in conditions such as keratitis, diabetic retinopathy, age-related macular degeneration, glaucoma, cataracts, dry eye disease, keratoconus, uveitis, and pterygium. Their role in influencing metalloproteinases and cytokines, as well as endothelial permeability, and their protective effects on Müller cells against oxidative stress further highlight their diverse and critical roles in ocular pathologies. This review provides a comprehensive overview of the etiology and functions of SerpinA1 and SerpinA3 in ocular diseases, emphasizing their multifaceted roles and the complexity of their interactions within the ocular microenvironment.

The versatile role of Serpina3c in physiological and pathological processes: a review of recent studies

Murine Serpina3c belongs to the family of serine protease inhibitors (Serpins), clade "A" and its human homologue is SerpinA3. Serpina3c is involved in some physiological processes, including insulin secretion and adipogenesis. In the pathophysiological process, the deletion of Serpina3c leads to more severe metabolic disorders, such as aggravated non-alcoholic fatty liver disease (NAFLD), insulin resistance and obesity. In addition, Serpina3c can improve atherosclerosis and regulate cardiac remodeling after myocardial infarction. Many of these processes are directly or indirectly mediated by its inhibition of serine protease activity. Although its function has not been fully revealed, recent studies have shown its potential research value. Here, we aimed to summarize recent studies to provide a clearer view of the biological roles and the underlying mechanisms of Serpina3c.

Gadolinium-Cyclic 1,4,7,10-Tetraazacyclododecane-1,4,7,10-Tetraacetic Acid-Click-Sulfonyl Fluoride for Probing Serine Protease Activity in Magnetic Resonance Imaging

Serine protease is linked to a wide range of diseases, prompting the development of robust, selective, and sensitive protease assays and sensing methods. However, the clinical needs for serine protease activity imaging have not yet been met, and the efficient in vivo detection and imaging of serine protease remain challenging. Here, we report the development of the gadolinium-cyclic 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid-click-Sulfonyl Fluoride (Gd-DOTA-click-SF) MRI contrast agent targeting serine protease. The HR-FAB mass spectrum confirmed the successful formation of our designed chelate. The molar longitudinal relaxivity (r₁) of the Gd-DOTA-click-SF probe (r₁ = 6.82 mM^-1 s^-1) was significantly higher than that of Dotarem (r₁ = 4.63 mM^-1 s^-1), in the range of 0.01-0.64 mM at 9.4 T. The in vitro cellular study and the transmetallation kinetics study showed that the safety and stability of this probe are comparable to those of conventional Dotarem. Ex vivo abdominal aortic aneurysm (AAA) MRI revealed that this probe has a contrast-agent-to-noise ratio (CNR) that is approximately 51 ± 23 times greater than that of Dotarem. This study of superior visualization of AAA suggests that it has the potential to detect elastase in vivo and supports the feasibility of probing serine protease activity in T1-weighted MRI.

Identification MNS1, FRZB, OGN, LUM, SERP1NA3 and FCN3 as the potential immune-related key genes involved in ischaemic cardiomyopathy by random forest and nomogram

The immune molecular mechanisms involved in ischaemic cardiomyopathy (ICM) have not been fully elucidated. The current study aimed to elucidate the immune cell infiltration pattern of the ICM and identify key immune-related genes that participate in the pathologic process of the ICM. The differentially expressed genes (DEGs) were identified from two datasets (GSE42955 combined with GSE57338) and the top 8 key DEGs related to ICM were screened using random forest and used to construct the nomogram model. Moreover, the "CIBERSORT" software package was used to determine the proportion of infiltrating immune cells in the ICM. A total of 39 DEGs (18 upregulated and 21 downregulated) were identified in the current study. Four upregulated DEGs, including MNS1, FRZB, OGN, and LUM, and four downregulated DEGs, SERP1NA3, RNASE2, FCN3 and SLCO4A1, were identified by the random forest model. The nomogram constructed based on the above 8 key genes suggested a diagnostic value of up to 99% to distinguish the ICM from healthy participants. Meanwhile, most of the key DEGs presented prominent interactions with immune cell infiltrates. The RT-qPCR results suggested that the expression levels of MNS1, FRZB, OGN, LUM, SERP1NA3 and FCN3 between the ICM and control groups were consistent with the bioinformatic analysis results. These results suggested that immune cell infiltration plays a critical role in the occurrence and progression of ICM. Several key immune-related genes, including the MNS1, FRZB, OGN, LUM, SERP1NA3 and FCN3 genes, are expected to be reliable serum markers for the diagnosis of ICM and potential molecular targets for ICM immunotherapy.

The Search for Associations of Serum Proteins with the Presence of Unstable Atherosclerotic Plaque in Coronary Atherosclerosis

To study the associations of blood proteins with the presence of unstable atherosclerotic plaques in the arteries of patients with coronary atherosclerosis using quantitative proteomics. The studies involved two groups of men with coronary atherosclerosis (group 1 (St) had only stable atherosclerotic plaques; group 2 (Ns) had only unstable atherosclerotic plaques, according to histological analysis of tissue samples); the average age of patients was 57.95 ± 7.22. Protein concentrations in serum samples were determined using the PeptiQuant Plus Proteomics Kit. The identification of protein fractions was carried out by monitoring multiple reactions on a Q-TRAP 6500 mass spectrometer combined with a liquid chromatograph. Mass spectrometric identification revealed in serum samples from patients with unstable atherosclerotic plaques a reduced concentration of proteins in the blood: α-1-acid glycoprotein, α-1-antichymotrypsin, α-1-antitrypsin, ceruloplasmin, hemopexin, haptoglobin, apolipoprotein B-100, apolipoprotein L1, afamin and complement component (C3, C7, C9). Moreover, at the same time a high concentration complements factor H and attractin. The differences were considered significant at p < 0.05. It was found that the instability of atherosclerotic plaques is associated with the concentration of proteins: afamin, attractin, components of the complement system, hemopexin and haptoglobin. The data of our study showed the association of some blood proteins with the instability of atherosclerotic plaques in coronary atherosclerosis. Their potential role in the development of this disease and the possibility of using the studied proteins as biomarkers requires further research.

Immune-related SERPINA3 as a biomarker involved in diabetic nephropathy renal tubular injury

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease and has become a serious medical issue globally. Although it is known to be associated with glomerular injury, tubular injury has been found to participate in DN in recent years. However, mechanisms of diabetic renal tubular injury remain unclear. Here, we investigated the differentially expressed genes in the renal tubules of patients with DN by analyzing three RNA-seq datasets downloaded from the Gene Expression Omnibus database. Gene set enrichment analysis and weighted gene co-expression network analysis showed that DN is highly correlated with the immune system. The immune-related gene SERPINA3 was screened out with lasso regression and Kaplan–Meier survival analyses. Considering that SERPINA3 is an inhibitor of mast cell chymase, we examined the expression level of SERPINA3 and chymase in human renal tubular biopsies and found that SERPINA3 was upregulated in DN tubules, which is consistent with the results of the differential expression analysis. Besides, the infiltration and degranulation rates of mast cells are augmented in DN. By summarizing the biological function of SERPINA3, chymase, and mast cells in DN based on our results and those of previous studies, we speculated that SERPINA3 is a protective immune-related molecule that prevents renal tubular injury by inhibiting the proliferation and activation of mast cells and downregulating the activity of chymase.

Unfolding the cascade of SERPINA3: Inflammation to cancer

SERine Protease INhibitor clade A member 3 (SERPINA3), a member of the SERine-Protease INhibitor (SERPIN) superfamily, principally works as a protease inhibitor in maintaining cellular homeostasis. It is a matricellular acute-phase glycoprotein that appears to be the sole nuclear-binding secretory serpin. Several studies have emerged in recent years demonstrating its link to cancer and disease biology. SERPINA3 seems to have cancer- and compartment-specific biological functions, acting either as a tumour promoter or suppressor in different cancers. However, the localization, mechanism of action and the effectors of SERPINA3 in physiological and pathological scenarios remain obscure. Our review aims to consolidate the current evidence of SERPINA3 in various cancers, highlighting its association with the cancer hallmarks and ratifying its status as an emerging cancer biomarker. The elucidation of SERPINA3-mediated cancer progression and its targeting might shed light on the realm of cancer therapeutics.

10,12-conjugated linoleic acid supplementation improves HDL composition and function in mice

Obesity is associated with inflammation, insulin resistance, and type 2 diabetes, which are major risk factors for CVD. One dietary component of ruminant animal foods, 10,12-conjugated linoleic acid (10,12 CLA), has been shown to promote weight loss in humans. Previous work has shown that 10,12 CLA is atheroprotective in mice by a mechanism that may be distinct from its weight loss effects, but this exact mechanism is unclear. To investigate this, we evaluated HDL composition and function in obese LDL receptor (Ldlr^−/−) mice that were losing weight because of 10,12 CLA supplementation or caloric restriction (CR; weight-matched control group) and in an obese control group consuming a high-fat high-sucrose diet. We show that 10,12 CLA-HDL exerted a stronger anti-inflammatory effect than CR- or high-fat high-sucrose-HDL in cultured adipocytes. Furthermore, the 10,12 CLA-HDL particle (HDL-P) concentration was higher, attributed to more medium- and large-sized HDL-Ps. Passive cholesterol efflux capacity of 10,12 CLA-HDL was elevated, as was expression of HDL receptor scavenger receptor class B type 1 in the aortic arch. Murine macrophages treated with 10,12 CLA in vitro exhibited increased expression of cholesterol transporters Abca1 and Abcg1, suggesting increased cholesterol efflux potential of these cells. Finally, proteomics analysis revealed elevated Apoa1 content in 10,12 CLA-HDL-Ps, consistent with a higher particle concentration, and particles were also enriched with alpha-1-antitrypsin, an emerging anti-inflammatory and antiatherosclerotic HDL-associated protein. We conclude that 10,12 CLA may therefore exert its atheroprotective effects by increasing HDL-P concentration, HDL anti-inflammatory potential, and promoting beneficial effects on cholesterol efflux.

Proteomic analysis of serum proteins in children with brain death

BACKGROUND

Brain death (BD) is a catastrophic physiological outcome that can occur in individuals with terminal illness and can adversely affect the graft quality after donation of their organs. As BD has no specific symptoms, it can be difficult to diagnose in a timely manner. The present study was designed to investigate the serum protein expression profiles of children affected by BD in an effort to define diagnostic biomarkers for this condition.

METHODS

Blood samples were collected from 8 patients with BD and 8 healthy controls during the same time period. Tandem mass tags and mass spectrometry were used to conduct a proteomic analysis of serum extracted from the samples. The potential regulatory roles of the top 5 upregulated and downregulated proteins identified through the analysis were then explored using bioinformatics analyses and a review of the related literature.

RESULTS

The top 5 upregulated proteins in the serum samples from patients with BD were lipopolysaccharide-binding protein (LBP), α1-acid glycoprotein (α1-AGP), α1-antichymotrypsin (α1-ACT), leucine-rich α1-glycoprotein (LRG1), and lactate dehydrogenase B heavy chain (LDHB), and the 5 most downregulated proteins in these samples were actin-binding protein 2 (transgelin-2), platelet basic protein (PBP), tropomyosin α4 chain (TPM4), tropomyosin α3 chain (TPM3), and peptidase inhibitor 16 (PI16). Literature searches indicated that several of the identified proteins influence the pathogeneses of various diseases, with LBP, α1-AGP, α1-ACT, LRG1, transgelin-2, and PBP all being related to inflammatory activity.

CONCLUSIONS

Through a proteomics-based analysis, several differentially expressed proteins were identified in patients with BD relative to healthy controls. Most of these proteins are associated with inflammatory responses that have the potential to persist after the occurrence of BD. Further clinical work is needed to clarify the functional roles of the identified proteins.

The Association and Pathogenesis of SERPINA3 in Coronary Artery Disease

Background: Serine proteinase inhibitor A3 (SERPINA3) has been discovered in the pathogenesis of many human diseases, but little is known about the role of SERPINA3 in coronary artery disease (CAD). Therefore, we aim to determine its relationship with CAD and its function in the pathogenesis of atherosclerosis.

Methods: In total 86 patients with CAD and 64 patients with non-CAD were compared. The plasma SERPINA3 levels were measured using ELISA. Logistic regression analysis and receiver-operating characteristic (ROC) analysis were performed to illustrate the association between plasma SERPINA3 levels and CAD. In vitro, real-time PCR (RT-PCR) and immunofluorescence staining were used to determine the expression of SERPINA3 in atherosclerotic plaques and their component cells. Then rat aortic smooth muscle cells (RASMCs) were transfected with siRNA to knock down the expression of SERPINA3 and human umbilical vein endothelial cells (HUVECs) were stimulated by SERPINA3 protein. EdU assay and scratch assay were used for assessing the capability of proliferation and migration. The cell signaling pathway was evaluated by western blot and RT-PCR.

Results: Patients with CAD [104.4(54.5–259.2) μg/mL] had higher levels of plasma SERPINA3 than non-CAD [65.3(47.5–137.3) μg/mL] (P = 0.004). After being fully adjusted, both log-transformed and tertiles of plasma SERPINA3 levels were significantly associated with CAD. While its diagnostic value was relatively low since the area under the ROC curve was 0.64 (95% CI: 0.55–0.73). Secreted SERPINA3 might increase the expression of inflammatory factors in HUVECs. Vascular smooth muscle cells had the highest SERPINA3 expression among the aorta compared to endothelial cells and inflammatory cells. The knockdown of SERPINA3 in RASMCs attenuated its proliferation and migration. The phosphorylated IκBα and its downstream pathway were inhibited when SERPINA3 was knocked down.

Conclusions: Elevated plasma SERPINA3 levels were associated with CAD. SERPINA3 can increase inflammatory factors expression in HUVECs. It can regulate VSMCs proliferation, migration, and releasing of inflammatory factors through the NF-κB signaling pathway. Thus, SERPINA3 played a significant role in the pathogenesis of atherosclerosis.

SerpinA3N attenuates ischemic stroke injury by reducing apoptosis and neuroinflammation

Objective

To assess the effect of serine protein inhibitor A3N (serpinA3N) in ischemic stroke and to explore its mechanism of action.

Methods

Mouse ischemic stroke model was induced by transient middle cerebral artery occlusion followed by reperfusion. The expression pattern of serpinA3N was assessed using immunofluorescence, Western blot analysis, and real‐time quantitative PCR. An adeno‐associated virus (AAV) and recombinant serpinA3N were administered. Additionally, co‐immunoprecipitation‐mass spectrometry and immunofluorescence co‐staining were used to identify protein interactions.

Results

SerpinA3N was upregulated in astrocytes and neurons within the ischemic penumbra after stroke in the acute phase. The expression of serpinA3N gradually increased 6 h after reperfusion, peaked on the day 2–3, and then decreased by day 7. Overexpression of serpinA3N by AAV significantly reduced the infarct size and improved motor function, associated with alleviated inflammation and oxidative stress. SerpinA3N treatment also reduced apoptosis both in vivo and in vitro. Co‐immunoprecipitation‐mass spectrometry and Western blotting revealed that clusterin interacts with serpinA3N, and Akt‐mTOR pathway members were upregulated by serpinA3N both in vivo and in vitro.

Conclusions

SerpinA3N is expressed in astrocytes and penumbra neurons after stroke in mice. It reduces brain damage possibly via interacting with clusterin and inhibiting neuronal apoptosis and neuroinflammation.

Identification of biomarkers of brown adipose tissue aging highlights the role of dysfunctional energy and nucleotide metabolism pathways

Brown adipose tissue function declines during aging and may contribute to the onset of metabolic disorders such as diabetes and obesity. Only limited understanding of the mechanisms leading to the metabolic impairment of brown adipocytes during aging exists. To this end, interscapular brown adipose tissue samples were collected from young and aged mice for quantification of differential gene expression and metabolite levels. To identify potential processes involved in brown adipocyte dysfunction, metabolite concentrations were correlated to aging and significantly changed candidates were subsequently integrated with a non-targeted proteomic dataset and gene expression analyses. Our results include novel age-dependent correlations of polar intermediates in brown adipose tissue. Identified metabolites clustered around three biochemical processes, specifically energy metabolism, nucleotide metabolism and vitamin metabolism. One mechanism of brown adipose tissue dysfunction may be linked to mast cell activity, and we identify increased histamine levels in aged brown fat as a potential biomarker. In addition, alterations of genes involved in synthesis and degradation of many metabolites were mainly observed in the mature brown adipocyte fraction as opposed to the stromal vascular fraction. These findings may provide novel insights on the molecular mechanisms contributing to the impaired thermogenesis of brown adipocytes during aging.

Endothelial cell infection and dysfunction, immune activation in severe COVID-19

Rationale: Pulmonary vascular endotheliitis, perivascular inflammation, and immune activation are observed in COVID-19 patients. While the initial SARS-CoV-2 infection mainly infects lung epithelial cells, whether it also infects endothelial cells (ECs) and to what extent SARS-CoV-2-mediated pulmonary vascular endotheliitis is associated with immune activation remain to be determined. Methods: To address these questions, we studied SARS-CoV-2-infected K18-hACE2 (K18) mice, a severe COVID-19 mouse model, as well as lung samples from SARS-CoV-2-infected nonhuman primates (NHP) and patient deceased from COVID-19. We used immunostaining, RNAscope, and electron microscopy to analyze the organs collected from animals and patient. We conducted bulk and single cell (sc) RNA-seq analyses, and cytokine profiling of lungs or serum of the severe COVID-19 mice. Results: We show that SARS-CoV-2-infected K18 mice develop severe COVID-19, including progressive body weight loss and fatality at 7 days, severe lung interstitial inflammation, edema, hemorrhage, perivascular inflammation, systemic lymphocytopenia, and eosinopenia. Body weight loss in K18 mice correlated with the severity of pneumonia, but not with brain infection. We also observed endothelial activation and dysfunction in pulmonary vessels evidenced by the up-regulation of VCAM1 and ICAM1 and the downregulation of VE-cadherin. We detected SARS-CoV-2 in capillary ECs, activation and adhesion of platelets and immune cells to the vascular wall of the alveolar septa, and increased complement deposition in the lungs, in both COVID-19-murine and NHP models. We also revealed that pathways of coagulation, complement, K-ras signaling, and genes of ICAM1 and VCAM1 related to EC dysfunction and injury were upregulated, and were associated with massive immune activation in the lung and circulation. Conclusion: Together, our results indicate that SARS-CoV-2 causes endotheliitis via both infection and infection-mediated immune activation, which may contribute to the pathogenesis of severe COVID-19 disease.

Linagliptin, A Xanthine-Based Dipeptidyl Peptidase-4 Inhibitor, Ameliorates Experimental Autoimmune Myocarditis

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Treatment with linagliptin, a DPP-4 inhibitor, alleviates not only EAM but also ICIM.

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DPP-4 physically interacts with cathepsin G and enhances its activity.

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Linagliptin promotes SerpinA3N activity, thereby suppressing cathepsin G activity.

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Cathepsin G aggravates EAM through upregulating angiotensin II.

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Linagliptin suppresses oxidative stress in EAM hearts.

This study sought to show the mechanism of how to ameliorate experimental autoimmune myocarditis (EAM) by administering dipeptidyl peptidase (DPP)-4 inhibitor linagliptin. The number of RAR-related orphan nuclear receptor gamma–positive Th17 cells infiltrated to the EAM myocardium was significantly attenuated by linagliptin treatment. Tandem mass spectrometry–based analysis demonstrated that DPP-4 binds to cathepsin G in EAM hearts, thereby protecting cathepsin G activity through inhibiting SerpinA3N activity. Linagliptin suppresses oxidative stress in EAM hearts as well. Thus, we found that DPP-4 plays a detrimental role in the progression of EAM by interacting with cathepsin G, which, in turn, suppresses SerpinA3N activity.

Identification of potential genes associated with immune cell infiltration in atherosclerosis

BACKGROUND

This study aimed to analyze the potential genes associated with immune cell infiltration in atherosclerosis (AS).

METHODS

Gene expression profile data (GSE57691) of human arterial tissue samples were downloaded, and differentially expressed RNAs (DERNAs; long-noncoding RNA [lncRNAs], microRNAs [miRNAs], and messenger RNAs [mRNAs]) in AS vs. control groups were selected. Based on genome-wide expression levels, the proportion of infiltrating immune cells in each sample was assessed. Genes associated with immune infiltration were selected, and subjected to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. Finally, a competing endogenous RNA (ceRNA) network was constructed, and the genes in the network were subjected to functional analyses.

RESULTS

A total of 1749 DERNAs meeting the thresholds were screened, including 1673 DEmRNAs, 63 DElncRNAs, and 13 DEmiRNAs. The proportions of B cells, CD4+ T cells, and CD8+ T cells were significantly different between the two groups. In total, 341 immune-associated genes such as HBB, FCN1, IL1B, CXCL8, RPS27A, CCN3, CTSZ, and SERPINA3 were obtained that were enriched in 70 significantly related GO biological processes (such as immune response) and 15 KEGG pathways (such as chemokine signaling pathway). A ceRNA network, including 33 lncRNAs, 11 miRNAs, and 216 mRNAs, was established.

CONCLUSION

Genes such as FCN1, IL1B, and SERPINA3 may be involved in immune cell infiltration and may play important roles in AS progression via ceRNA regulation.

Protective role of serpina3c as a novel thrombin inhibitor against atherosclerosis in mice

Abnormal vascular smooth muscle cell (VSMC) proliferation is a critical step in the development of atherosclerosis. Serpina3c is a serine protease inhibitor (serpin) that plays a key role in metabolic diseases. The present study aimed to investigate the role of serpina3c in atherosclerosis and regulation of VSMC proliferation and possible mechanisms. Serpina3c is down-regulated during high-fat diet (HFD)-induced atherosclerosis. An Apoe-/-/serpina3c-/--double-knockout mouse model was used to determine the role of serpina3c in atherosclerosis after HFD for 12 weeks. Compared with Apoe-/- mice, the Apoe-/-/serpina3c-/- mice developed more severe atherosclerosis, and the number of VSMCs and macrophages in aortic plaques was significantly increased. The present study revealed serpina3c as a novel thrombin inhibitor that suppressed thrombin activity. In circulating plasma, thrombin activity was high in the Apoe-/-/serpina3c-/- mice, compared with Apoe-/- mice. Immunofluorescence staining showed thrombin and serpina3c colocalization in the liver and aortic cusp. In addition, inhibition of thrombin by dabigatran in serpina3c-/- mice reduced neointima lesion formation due to partial carotid artery ligation. Moreover, an in vitro study confirmed that thrombin activity was also decreased by serpina3c protein, supernatant and cell lysate that overexpressed serpina3c. The results of experiments showed that serpina3c negatively regulated VSMC proliferation in culture. The possible mechanism may involve serpina3c inhibition of ERK1/2 and JNK signaling in thrombin/PAR-1 system-mediated VSMC proliferation. Our results highlight a protective role for serpina3c as a novel thrombin inhibitor in the development of atherosclerosis, with serpina3c conferring protection through the thrombin/PAR-1 system to negatively regulate VSMC proliferation through ERK1/2 and JNK signaling.

Proteomic Analysis of Peri-Wounding Tissue Expressions in Extracorporeal Shock Wave Enhanced Diabetic Wound Healing in a Streptozotocin-Induced Diabetes Model

Our former studies have demonstrated that extracorporeal shock wave therapy (ESWT) could enhance diabetic wound healing but the bio-mechanisms remain elusive. This study investigated the changes of topical peri-wounding tissue expressions after ESWT in a rodent streptozotocin-induced diabetic wounding model by using the proteomic analysis and elucidated the molecular mechanism. Diabetic rats receiving ESWT, normal control, and diabetic rats receiving no therapy were analyzed. The spots of interest in proteome analysis were subjected to mass spectrometry to elucidate the peptide mass fingerprints. Protein expression was validated using immunohistochemical staining and related expression of genes were analyzed using real-time RT-PCR. The proteomic data showed a significantly higher abundance of hemopexin at day 3 of therapy but down-regulation at day 10 as compared to diabetic control. In contrast, the level of serine proteinase inhibitor (serpin) A3N expression was significantly decreased at day 3 therapy but expression was upregulated at day 10. Using real-time RT-PCR revealed that serpin-related EGFR-MAPK pathway was involved in ESWT enhanced diabetic wound healing. In summary, proteome analyses demonstrated the expression change of hemopexin and serpin with related MAPK signaling involved in ESWT-enhanced diabetic wound healing. Modulation of hemopexin and serpin related pathways are good strategies to promote wound healing.

Inhibition of SERPINA3N-dependent neuroinflammation is essential for melatonin to ameliorate trimethyltin chloride-induced neurotoxicity

Trimethyltin chloride (TMT) is a potent neurotoxin that causes neuroinflammation and neuronal cell death. Melatonin is a well-known anti-inflammatory agent with significant neuroprotective activity. Male C57BL/6J mice were intraperitoneally injected with a single dose of melatonin (10 mg/kg) before exposure to TMT (2.8 mg/kg, ip). Thereafter, the mice received melatonin (10 mg/kg, ip) once a day for another three consecutive days. Melatonin dramatically alleviated TMT-induced neurotoxicity in mice by attenuating hippocampal neuron loss, inhibiting epilepsy-like seizures, and ameliorating memory deficits. Moreover, melatonin markedly suppressed TMT-induced neuroinflammatory responses and astrocyte activation, as shown by a decrease in inflammatory cytokine production as well as the downregulation of neurotoxic reactive astrocyte phenotype markers. Mechanistically, serine peptidase inhibitor clade A member 3N (SERPINA3N) was identified as playing a central role in the protective effects of melatonin based on quantitative proteome and bioinformatics analysis. Most importantly, melatonin significantly suppressed TMT-induced SERPINA3N upregulation at both the mRNA and protein levels. The overexpression of Serpina3n in the mouse hippocampus abolished the protective effects of melatonin on TMT-induced neuroinflammation and neurotoxicity. Melatonin protected cells against TMT-induced neurotoxicity by inhibiting SERPINA3N-mediated neuroinflammation. Melatonin may be a promising and practical agent for reducing TMT-induced neurotoxicity in clinical practice.

Proteomics and multivariate modelling reveal sex-specific alterations in distinct regions of human carotid atheroma

Background

Atherosclerotic lesions are comprised of distinct regions with different proteomic profiles. Men and women develop differences in lesion phenotype, with lesions from women generally being more stable and less prone to rupture. We aimed to investigate the differences in proteomic profiles between sexes, including distinct lesion regions, to identify altered proteins that contribute to these differences observed clinically.

Methods

Carotid endarterectomy samples (ten men/ten women) were obtained, and intraplaque biopsies from three distinct regions (internal control, fatty streak and plaque) were analysed by tandem-mass spectrometry. Multivariate statistical modelling, using orthogonal partial least square-discriminant analysis, was used to discriminate the proteomes between men and women.

Results

Multivariate discriminant modelling revealed proteins from 16 functional groups that displayed sex-specific associations. Additional statistics revealed ten proteins that display region-specific alterations when comparing sexes, including proteins related to inflammatory response, response to reactive oxygen species, complement activation, transport and blood coagulation. Transport protein afamin and blood coagulation proteins antithrombin-III and coagulation factor XII were significantly increased in plaque region from women. Inflammatory response proteins lysozyme C and phospholipase A2 membrane-associated were significantly increased in plaque region from men. Limitations with this study are the small sample size, limited patient information and lack of complementary histology to control for cell type differences between sexes.

Conclusions

This pilot study, for the first time, utilises a multivariate proteomic approach to investigate sexual dimorphism in human atherosclerotic tissue, and provides an essential proteomic platform for further investigations to help understand sexual dimorphism and plaque vulnerability in atherosclerosis.

Electronic supplementary material

The online version of this article (10.1186/s13293-018-0217-3) contains supplementary material, which is available to authorized users.

Sox9 is increased in arterial plaque and stenosis, associated with synthetic phenotype of vascular smooth muscle cells and causes alterations in extracellular matrix and calcification

Vascular smooth muscle cells (VSMC) exhibit a dual role in progression and maintenance of arteriosclerosis. They are fundamental for plaque stability but also can drive plaque progression. During pathogenic vascular remodeling, VSMC transdifferentiate into a phenotype with enhanced proliferation and migration. Moreover, they exert an increased capacity to generate extracellular matrix proteins. A special lineage of transdifferentiated VSMC expresses Sox9, a multi-functional transcription factor. The aim of the study was to examine the role of Sox9 in phenotypic alterations leading to arteriosclerosis. Using mouse models for arterial stenosis, Sox9 induction in diseased vessels was verified. The phenotypic switch of VSMC from contractile to proliferative nature caused a significant increase of Sox9 expression. Various factors known to be involved in the progression of arteriosclerosis were examined for their ability to modulate Sox9 expression in VSMC. While PDGF-BB resulted in a strong transient upregulation of Sox9, TGF-β1 appeared to be responsible for a moderate, but prolonged increase of Sox9 expression. Beside the regulation, functional studies focused on knockout and overexpression of Sox9. A Sox9-dependent alteration of extracellular matrix could be revealed and was associated with an upregulated calcium deposition. Taken together, Sox9 is identified as important factor of VSMC function by modulation the extracellular matrix composition and calcium deposition, which are important processes in plaque development.

MicroRNA regulation of extracellular matrix components in the process of atherosclerotic plaque destabilization

The process of atherosclerotic plaque destabilization, leading to myocardial infarction, is still not fully understood. The pathway - composed of structural and regulatory proteins of the extracellular matrix (ECM) such as collagen, elastin, small leucine-rich proteoglycans, metalloproteinases, cathepsins and serine proteases - is one potential way of atherosclerotic plaque destabilization. The expression of these proteins is controlled by different microRNA molecules. The goal of this paper is to summarize the current investigations and knowledge about ECM in the process of atherosclerotic plaque destabilization, giving special attention to epigenetic expression regulation by microRNA.

Long-term miR-29b suppression reduces aneurysm formation in a Marfan mouse model

Aortic root aneurysm formation and subsequent dissection and/or rupture remain the leading cause of death in patients with Marfan syndrome. Our laboratory has reported that miR‐29b participates in aortic root/ascending aorta extracellular matrix remodeling during early aneurysm formation in Fbn1^C1039G/+ Marfan mice. Herein, we sought to determine whether miR‐29b suppression can reduce aneurysm formation long‐term. Fbn1^C1039G/+ Marfan mice were treated with retro‐orbital LNA‐anti‐miR‐29b inhibitor or scrambled‐control‐miR before aneurysms develop either (1) a single dose prenatally (pregnant Fbn1^C1039G/+ mice at 14.5 days post‐coitum) (n = 8–10, each group) or (2) postnatally every other week, from 2 to 22 weeks of age, and sacrificed at 24 weeks (n = 8–10, each group). To determine if miR‐29b blockade was beneficial even after aneurysms develop, a third group of animals were treated every other week, starting at 8 weeks of age, until sacrificed (n = 4–6, each group). miR‐29b inhibition resulted in aneurysm reduction, increased elastogenesis, decreased matrix metalloproteinase activity and decreased elastin breakdown. Prenatal LNA‐anti‐miR‐29b inhibitor treatment decreased aneurysm formation up to age 32 weeks, whereas postnatal treatment was effective up to 16 weeks. miR‐29b blockade did not slow aortic growth once aneurysms already developed. Systemic miR‐29b inhibition significantly reduces aneurysm development long‐term in a Marfan mouse model. Drug administration during aortic wall embryologic development appears fundamental. miR‐29b suppression could be a potential therapeutic target for reducing aneurysm formation in Marfan syndrome patients.

Clonal expansion of T cells in abdominal aortic aneurysm: a role for doxycycline as drug of choice?

Most reported studies with animal models of abdominal aortic aneurysm (AAA) and several studies with patients have suggested that doxycycline favourably modifies AAA; however, a recent large long-term clinical trial found that doxycycline did not limit aneurysm growth. Thus, there is currently no convincing evidence that doxycycline reduces AAA expansion. Here, we critically review the available experimental and clinical information about the effects of doxycycline when used as a pharmacological treatment for AAA. The view that AAA can be considered an autoimmune disease and the observation that AAA tissue shows clonal expansion of T cells is placed in the light of the well-known inhibition of mitochondrial protein synthesis by doxycycline. In T cell leukaemia animal models, this inhibitory effect of the antibiotic has been shown to impede T cell proliferation, resulting in complete tumour eradication. We suggest that the available evidence of doxycycline action on AAA is erroneously ascribed to its inhibition of matrix metalloproteinases (MMPs) by competitive binding of the zinc ion co-factor. Although competitive binding may explain the inhibition of proteolytic activity, it does not explain the observed decreases of MMP mRNA levels. We propose that the observed effects of doxycycline are secondary to inhibition of mitochondrial protein synthesis. Provided that serum doxycycline levels are kept at adequate levels, the inhibition will result in a proliferation arrest, especially of clonally expanding T cells. This, in turn, leads to the decrease of proinflammatory cytokines that are normally generated by these cells. The drastic change in cell type composition may explain the changes in MMP mRNA and protein levels in the tissue samples.

Soluble elastin peptides in cardiovascular homeostasis: Foe or ally

Elastin peptides, also known as elastin-derived peptides or elastokines, are soluble polypeptides in blood and tissue. The blood levels of elastin peptides are usually low but can increase during cardiovascular diseases, such as atherosclerosis, aortic aneurysm and diabetes with vascular complications. Generally, elastin peptides are derived from the degradation of insoluble elastic polymers. The biological activities of elastin peptides are bidirectional, e.g., a pro-inflammatory effect on monocyte migration induction vs. a protective effect on vasodilation promotion. However, recent in vivo studies have demonstrated that elastin peptides promote the formation of atherosclerotic plaques in hypercholesterolemic mice and induce hyperglycemia and elevations in plasma lipid levels in fasted mice. More important, the detrimental effects induced by elastin peptides can be largely inhibited by genetic or pharmacological blockade of the elastin receptor complex or by neutralization of an antibody against elastin peptides. These studies indicate new therapeutic strategies for the treatment of cardiovascular diseases by targeting elastin peptide metabolism. Therefore, the goal of this review is to summarize current knowledge about elastin peptides relevant to cardiovascular pathologies to further delineate their potential application in cardiovascular disease.

Unc93b1 -Dependent Endosomal Toll-Like Receptor Signaling Regulates Inflammation and Mortality during Coxsackievirus B3 Infection

Coxsackievirus strain B serotype 3 (CVB3)-induced myocarditis is an important human disease that causes permanent tissue damage and can lead to death from acute infection or long-term morbidity caused by chronic inflammation. The timing and magnitude of immune activation following CVB3 infection can mediate a positive host outcome or increase tissue pathology. To better elucidate the role of endosomal Toll-like receptor (TLR) signaling in acute CVB3 infection, we studied mice with a loss-of-function mutation, known as Letr for 'loss of endosomal TLR response', in Unc93b1, which is a chaperone protein for TLR3, TLR7 and TLR9. Using Unc93b1(Letr/)(Letr) mice, we determined that Unc93b1-dependent TLR activation was essential for the survival of acute CVB3-induced myocarditis. We also determined that a lack of endosomal TLR signaling was associated with a higher viral load in target organs and that it increased inflammation, necrosis and fibrosis in cardiac tissue. Loss of Unc93b1 function was also associated with increased cardiac expression of Ifn-b and markers of tissue injury and fibrosis including Lcn2 and Serpina3n early after CVB3 infection. These observations establish a significant role for Unc93b1 in the regulation of the host inflammatory response to CVB3 infection and also reveal potential mediators of host tissue damage that merit further investigation in acute viral myocarditis.

Uncovering the cathepsin system in heart failure patients submitted to Left Ventricular Assist Device (LVAD) implantation

Background

In end-stage heart failure (HF), the implantation of a left ventricular assist device (LVAD) is able to induce reverse remodeling. Cellular proteases, such as cathepsins, are involved in the progression of HF. The aim of this study was to evaluate the role of cathepsin system in HF patients supported by LVAD, in order to determine their involvement in cardiac remodeling.

Methods

The expression of cysteine (CatB, CatK, CatL, CatS) and serine cathepsin (CatG), and relative inhibitors (Cystatin B, C and SerpinA3, respectively) was determined in cardiac biopsies of 22 patients submitted to LVAD (pre-LVAD) and compared with: 1) control stable chronic HF patients on medical therapy at the moment of heart transplantation without prior LVAD (HT, n = 7); 2) patients supported by LVAD at the moment of transplantation (post-LVAD, n = 6).

Results

The expression of cathepsins and their inhibitors was significantly higher in pre-LVAD compared to the HT group and LVAD induced a further increase in the cathepsin system. Significant positive correlations were observed between cardiac expression of cathepsins and their inhibitors as well as inflammatory cytokines. In the pre-LVAD group, a relationship of cathepsins with dilatative etiology and length of hospitalization was found.

Conclusions

A parallel activation of cathepsins and their inhibitors was observed after LVAD support. The possible clinical importance of these modifications is confirmed by their relation with patients’ outcome. A better discovery of these pathways could add more insights into the cardiac remodeling during HF.

Proteinases and plaque rupture: unblocking the road to translation

PURPOSE OF REVIEW

To review progress over the past 5 years in relating extracellular proteinases to plaque rupture, the cause of most myocardial infarctions, and consider the most promising prospects for developing related treatments.

RECENT FINDINGS

Cysteinyl cathepsins have been implicated in multiple macrophage functions that could promote plaque rupture. Cathepsin K is an attractive target because it is a collagenase and selective inhibitors are already being used in phase III clinical trials. Several serine proteinases clearly influence vascular remodelling and atherogenesis but important, unrelated actions limit their value as therapeutic targets. Among the metalloproteinases, new evidence supports roles for A Disintigrin and Metalloproteinases (ADAMs), including ADAM-10, ADAM-17 and ADAM-33, which suggest that selective inhibitors might be effective treatments. For ADAMs with ThromboSpondin domains (ADAMTSs), there are biological and genome-wide association data linking ADAMTS-7 to incidence of coronary heart disease but not increased risk of myocardial infarctions. In the case of matrix metalloproteinases (MMPs), selective inhibitors of MMP-12 and MMP-13 are available and may be appropriate for development as therapies. Novel targets, including MMP-8, MMP-10, MMP-14, MMP-19, MMP-25 and MMP-28, are also being considered.

SUMMARY

New opportunities exist to exploit proteinases as therapeutic targets in plaque rupture.

Cathepsin G activity lowers plasma LDL and reduces atherosclerosis

Cathepsin G (CatG), a serine protease present in mast cells and neutrophils, can produce angiotensin-II (Ang-II) and degrade elastin. Here we demonstrate increased CatG expression in smooth muscle cells (SMCs), endothelial cells (ECs), macrophages, and T cells from human atherosclerotic lesions. In low-density lipoprotein (LDL) receptor-deficient (Ldlr(-/-)) mice, the absence of CatG reduces arterial wall elastin degradation and attenuates early atherosclerosis when mice consume a Western diet for 3months. When mice consume this diet for 6months, however, CatG deficiency exacerbates atherosclerosis in aortic arch without affecting lesion inflammatory cell content or extracellular matrix accumulation, but raises plasma total cholesterol and LDL levels without affecting high-density lipoprotein (HDL) or triglyceride levels. Patients with atherosclerosis also have significantly reduced plasma CatG levels that correlate inversely with total cholesterol (r=-0.535, P<0.0001) and LDL cholesterol (r=-0.559, P<0.0001), but not with HDL cholesterol (P=0.901) or triglycerides (P=0.186). Such inverse correlations with total cholesterol (r=-0.504, P<0.0001) and LDL cholesterol (r=-0.502, P<0.0001) remain significant after adjusting for lipid lowering treatments among this patient population. Human CatG degrades purified human LDL, but not HDL. This study suggests that CatG promotes early atherogenesis through its elastinolytic activity, but suppresses late progression of atherosclerosis by degrading LDL without affecting HDL or triglycerides.

Cathepsin G deficiency reduces periaortic calcium chloride injury-induced abdominal aortic aneurysms in mice

OBJECTIVE

Cathepsin G (CatG) is a serine protease that mediates angiotensin I to angiotensin II (Ang-II) conversion and is highly expressed in human abdominal aortic aneurysms (AAAs). However, it remains untested whether this protease participates in the pathogenesis of AAA.

METHODS AND RESULTS

Immunofluorescent double staining demonstrated the expression of CatG in smooth muscle cells (SMCs), macrophages, and endothelial cells in human AAA lesions (n = 12) but not in AAA-free aortas (n = 10). Whereas inflammatory cytokines induced CatG expression, high glucose concentration increased CatG activity in producing Ang-II and angiotensin-converting enzyme in SMCs, which could be fully blocked by a CatG-selective inhibitor or its small interfering RNA. To test whether CatG contributes to AAA development, we generated CatG and low-density lipoprotein receptor double deficient (Ldlr(-/-)Ctsg(-/-)) mice and their littermate controls (Ldlr(-/-)Ctsg(+/+)). Absence of CatG did not affect Ang-II infusion-induced AAAs. In contrast, in Ang-II-independent AAAs induced by periaortic CaCl2 injury (n = 12 per group), CatG deficiency significantly reduced aortic diameter increase (58.33% ± 6.83% vs 31.67% ± 5.75%; P = .007), aortic lesion area (0.35 ± 0.04 mm(2) vs 0.21 ± 0.02 mm(2); P = .005), and aortic wall elastin fragmentation grade (2.75 ± 0.18 vs 1.58 ± 0.17; P = .002) along with reduced lesion collagen content grade (2.80 ± 0.17 vs 2.12 ± 0.17; P = .009) without affecting indices of lesion inflammation, angiogenesis, cell proliferation, or apoptosis. In vitro elastin degradation assays demonstrated that CaCl2-induced AAA lesions from Ldlr(-/-)Ctsg(-/-) mice contained much lower elastinolytic activity than in those from littermate control mice. Gelatin gel zymogram assay suggested that absence of CatG in CaCl2-induced AAA lesions also reduced the activity of elastinolytic matrix metalloproteinases 2 and 9.

CONCLUSIONS

CatG may contribute to CaCl2-induced experimental AAAs directly through its elastinolytic activity and indirectly by regulating lesion matrix metalloproteinases 2 and 9 activities. Increased expression of CatG in vascular and inflammatory cells of human AAAs and its increased activity in producing Ang-II and angiotensin-converting enzyme by SMCs suggest an additional mechanism by which CatG contributes to AAA lesion progression.

Exploring the human tear fluid: discovery of new biomarkers in multiple sclerosis

PURPOSE

Multiple sclerosis is the first cause of progressive neurological disability among young adults living in Western countries. Its diagnosis is mostly based on clinical evaluation, neuroimaging, and in some cases cerebrospinal fluid (CSF) analysis, but no definitive diagnostic test exists. We proposed here that the exploration of tears from multiple sclerosis patients could lead to the discovery of new biomarkers.

EXPERIMENTAL DESIGN

Thirty multiple sclerosis patients (20% men) recruited to the Geneva University Hospitals were included in our study (mean age ± SD [years]: 42.4 ± 15.9). Twenty-five control patients (32% men) were also enrolled (mean age ± SD [years]: 42.7±15.1). Tears, CSF or blood was collected for each patient. Three independent quantitative (tandem mass tag) experiments were carried out between tears from multiple sclerosis and control patients. Protein verification was performed by Western blot on tears and CSF and by ELISA on serum samples.

RESULTS

Combined proteomics analyses provided 185 identified tear proteins. Among the differential proteins, alpha-1 antichymotrypsin was the only one to be significantly increased in the three experiments with similar ratios (ratios 1.6 to 2.5, p < 0.05). Its tear, CSF and serum elevation were further confirmed by Western blot and ELISA, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE

This study supports the concept that modifications of the tear proteome can reflect biological abnormalities associated with multiple sclerosis and perhaps other inflammatory conditions affecting the CNS. In addition, alpha-1 antichymotrypsin elevation in tear fluid emerges as a promising biomarker for the diagnosis of multiple sclerosis.

Synergistic effects of hypertension and aging on cognitive function and hippocampal expression of genes involved in β-amyloid generation and Alzheimer's disease

Strong epidemiological and experimental evidence indicate that hypertension in the elderly predisposes to the development of Alzheimer's disease (AD), but the underlying mechanisms remain elusive. The present study was designed to characterize the additive/synergistic effects of hypertension and aging on the expression of genes involved in β-amyloid generation and AD in the hippocampus, an area of brain contributing to higher cognitive function, which is significantly affected by AD both in humans and in mouse models of the disease. To achieve that goal, we induced hypertension in young (3 mo) and aged (24 mo) C57BL/6 mice by chronic (4 wk) infusion of angiotensin II and assessed changes in hippocampal mRNA expression of genes involved in amyloid precursor protein (APP)-dependent signaling, APP cleavage, Aβ processing and Aβ-degradation, synaptic function, dysregulation of microtubule-associated τ protein, and apolipoprotein-E signaling. Aged hypertensive mice exhibited spatial memory impairments in the Y-maze and impaired performance in the novel object recognition assay. Surprisingly, hypertension in aging did not increase the expression of APP, β- and γ-secretases, or genes involved in tauopathy. These genes are all involved in the early onset form of AD. Yet, hypertension in aging was associated with changes in hippocampal expression of APP binding proteins, e.g., [Mint3/amyloid β A4 precursor protein-binding family A member 3 (APBA3), Fe65/amyloid β A4 precursor protein-binding family B member 1 (APBB1)], amyloid β (A4) precursor-like protein 1 (APLP1), muscarinic M1 receptor, and serum amyloid P component, all of which may have a role in the pathogenesis of late-onset AD. The hippocampal gene expression signature observed in aged hypertensive mice in the present study provides important clues for subsequent studies to elucidate the mechanisms by which hypertension may contribute to the pathogenesis and clinical manifestation of AD.

Mast cells and vascular diseases

Mast cells are increasingly being recognized as effector cells in many cardiovascular conditions. Many mast-cell-derived products such as tryptase and chymase can, through their enzymic action, have detrimental effects on blood vessel structure while mast cell-derived mediators such as cytokines and chemokines can perpetuate vascular inflammation. Mice lacking mast cells have been developed and these are providing an insight into how mast cells are involved in cardiovascular diseases and, as knowledge increase, mast cells may become a viable therapeutic target to slow progression of cardiovascular disease.

Elevation of plasma high-density lipoproteins inhibits development of experimental abdominal aortic aneurysms

OBJECTIVE

Patients with abdominal aortic aneurysms have lower concentrations of high-density lipoproteins (HDLs), leading us to investigate whether increasing plasma HDLs could influence aneurysm formation.

METHODS AND RESULTS

Using the angiotensin II-induced hypercholesterolemic and the CaCl(2)-induced normocholesterolemic mouse model of AAA, we investigated the hypothesis that elevation of HDLs inhibits AAA. HDLs elevated before or at the time of AAA induction reduced AAA formation in both models but had no effect on early ruptures. Analysis of protein lysates from specific aortic segments demonstrated site-specific effects of HDLs on early signal transduction and cellular attrition. We found that HDLs reduced extracellular signal related kinases 1/2 activation in the suprarenal segment, while having no effect on p38 mitogen-associated protein kinase activation in any aortic segment and inhibiting c-Jun N-terminal kinase activation in all aortic segments. In addition, HDL elevation inhibited angiotensin II-induced apoptosis while inducing autophagy in the suprarenal segment of the aorta. Using Illumina gene array profiling we investigated the ability of HDL to modulate basal suprarenal aortic gene expression.

CONCLUSIONS

Increasing plasma HDLs inhibit experimental AAA formation, independent of hypercholesterolemia via reduced extracellular signal related kinases 1/2 activation and alteration of the balance of cellular attrition. HDLs modulate genes involved in matrix remodelling, cell migration, and proliferation.