ADAM17 (TACE) regulates TGFβ signaling through the cleavage of vasorin. Oncogene. 2011;30:1912-1922. [PMID: 21170088 DOI: 10.1038/onc.2010.565]

Vasorin (VASN) overexpression promotes pulmonary metastasis and resistance to adjuvant chemotherapy in patients with locally advanced rectal cancer

BACKGROUND

LARC patients commonly receive adjuvant therapy, however, hidden micrometastases still limit the improvement of OS. This study aims to investigate the impact of VASN in rectal cancer with pulmonary metastasis and understand the underlying molecular mechanisms to guide adjuvant chemotherapy selection.

METHODS

Sequencing data from rectal cancer patients with pulmonary metastasis from Sun Yat-sen University Cancer Center (SYSUCC) and publicly available data were meticulously analyzed. The functional role of VASN in pulmonary metastasis was validated in vivo and in vitro. Coimmunoprecipitation (co-IP), immunofluorescence, and rescue experiments were conducted to unravel potential molecular mechanisms of VASN. Moreover, VASN expression levels in tumor samples were examined and analyzed for their correlations with pulmonary metastasis status, tumor stage, adjuvant chemotherapy benefit, and survival outcome.

RESULTS

Our study revealed a significant association between high VASN expression and pulmonary metastasis in LARC patients. Experiments in vitro and in vivo demonstrated that VASN could promote the cell proliferation, metastasis, and drug resistance of colorectal cancer. Mechanistically, VASN interacts with the NOTCH1 protein, leading to concurrent activation of the NOTCH and MAPK pathways. Clinically, pulmonary metastasis and advanced tumor stage were observed in 90% of VASN-positive patients and 53.5% of VASN-high patients, respectively, and VASN-high patients had a lower five-year survival rate than VASN-low patients (26.7% vs. 83.7%). Moreover, the Cox analysis and OS analysis indicated that VASN was an independent prognostic factor for OS (HR = 7.4, P value < 0.001) and a predictor of adjuvant therapy efficacy in rectal cancer.

CONCLUSIONS

Our study highlights the role of VASN in decreasing drug sensitivity and activating the NOTCH and MAPK pathways, which leads to tumorigenesis and pulmonary metastasis. Both experimental and clinical data support that rectal cancer patients with VASN overexpression detected in biopsies have a higher risk of pulmonary metastasis and adjuvant chemotherapy resistance.

Zinc-Alpha-2-Glycoprotein Peptide Downregulates Type I and III Collagen Expression via Suppression of TGF-β and p-Smad 2/3 Pathway in Keloid Fibroblasts and Rat Incisional Model

BACKGROUND

Keloids and hypertrophic scars result from abnormal collagen accumulation and the inhibition of its degradation. Although the pathogenesis remains unclear, excessive accumulation of the extracellular matrix (ECM) is believed to be associated with the TGF-β/SMAD pathway. Zinc-alpha-2-glycoprotein (ZAG) inhibits TGF-β-mediated epithelial-to-mesenchymal transdifferentiation and impacts skin barrier functions. In this study, we investigated the potential of a small ZAG-derived peptide against hypertrophic scars and keloids.

METHODS

The study examined cell proliferation and mRNA expression of collagen types I and III in human dermal fibroblast (HDF) cell lines and keloid-derived fibroblasts (KF) following ZAG peptide treatment. A rat incisional wound model was used to evaluate the effect of ZAG peptide in scar tissue.

RESULTS

Significantly lower mRNA levels of collagen types I and III were observed in ZAG-treated fibroblasts, whereas matrix metalloproteinase (MMP)-1 and MMP-3 mRNA levels were significantly increased in HDFs and KFs. Furthermore, ZAG peptide significantly reduced protein expression of collagen type I and III, TGF-β1, and p-Smad2/3 complex in KFs. Rat incisional scar models treated with ZAG peptide presented narrower scar areas and reduced immature collagen deposition, along with decreased expression of collagen type I, α-SMA, and p-Smad2/3.

CONCLUSION

ZAG peptide effectively suppresses the TGF-β and p-Smad2/3 pathway and inhibits excessive cell proliferation during scar formation, suggesting its potential therapeutic implications against keloids and hypertrophic scars.

Decreased Extracellular Vesicle Vasorin in Severe Preeclampsia Plasma Mediates Endothelial Dysfunction

Background

Preeclampsia (PE) is a serious pregnancy complication affecting 5-8% of pregnancies globally. It is a leading cause of maternal and neonatal morbidity and mortality. Despite its prevalence, the underlying mechanisms of PE remain unclear. This study aimed to determine the potential role of vasorin (VASN) in PE pathogenesis by investigating its levels in extracellular vesicles (EV) and its effects on vascular function.

Methods & Results

We conducted unbiased proteomics on urine-derived EV from severe PE (sPE) and normotensive pregnant women (NTP), identifying differential protein abundances. Out of one hundred and twenty proteins with ≥ ±1.5-fold regulation at P<0.05 between sPE and NTP, we focused on Vasorin (VASN), which is downregulated in sPE in urinary EV, in plasma EV and in the placenta and is a known regulator of vascular function. We generated EV with high VASN content from both human and murine placenta explants (Plex EV), which recapitulated disease-state-dependent effects on vascular function observed when treating murine aorta rings (MAR) or human aortic endothelial cells (HAEC) with murine or human plasma-derived EV. In normal murine pregnancy, VASN increases with gestational age (GA), and VASN is decreased in plasma EV, in placenta tissue and in Plex EV after intravenous administration of adenovirus encoding short FMS-like tyrosine kinase 1 (sFLT-1), a murine model of PE (murine-PE). VASN is decreased in plasma EV, in placenta tissue and in EV isolated from conditioned media collected from placenta explants (Plex EV) in patients with sPE as compared to NTP. Human sPE and murine-PE plasma EV and Plex EV impair migration, tube formation, and induces apoptosis in human aortic endothelial cells (HAEC) and inhibit acetylcholine-induced vasorelaxation in murine vascular rings (MAR). VASN over-expression counteracts the effects of sPE EV treatment in HAEC and MAR. RNA sequencing revealed that over-expression or knock down of VASN in HAEC results in contrasting effects on transcript levels of hundreds of genes associated with vasculogenesis, endothelial cell proliferation, migration and apoptosis.

Conclusions

The data suggest that VASN, delivered to the endothelium via EV, regulates vascular function and that the loss of EV VASN may be one of the mechanistic drivers of PE.

CLINICAL PERSPECTIVE

What is NewVASN in circulating plasma EV in sPE is reduced compared with VASN content in plasma EV of gestational age-matched pregnant women.VASN is encapsulated and transported in EV and plays a pro-angiogenic role during pregnancy.VASN should be explored both for its pro-angiogenic mechanistic role and as a novel biomarker and potential predictive diagnostic marker for the onset and severity of PE.What Are the Clinical Implications?VASN plays a role in maintaining vascular health and the normal adaptive cardiovascular response in pregnancy. A decrease of VASN is observed in sPE patients contributing to cardiovascular maladaptation.Strategies to boost diminished VASN levels and/or to pharmacologically manipulate mechanisms downstream of VASN may be explored for potential therapeutic benefit in PE.The decrease in EV-associated VASN could potentially be used as a (predictive) biomarker for PE.

iRhom2 regulates ectodomain shedding and surface expression of the major histocompatibility complex (MHC) class I

Proteolytic release of transmembrane proteins from the cell surface, the so called ectodomain shedding, is a key process in inflammation. Inactive rhomboid 2 (iRhom2) plays a crucial role in this context, in that it guides maturation and function of the sheddase ADAM17 (a disintegrin and metalloproteinase 17) in immune cells, and, ultimately, its ability to release inflammatory mediators such as tumor necrosis factor α (TNFα). Yet, the macrophage sheddome of iRhom2/ADAM17, which is the collection of substrates that are released by the proteolytic complex, is only partly known. In this study, we applied high-resolution proteomics to murine and human iRhom2-deficient macrophages for a systematic identification of substrates, and therefore functions, of the iRhom2/ADAM17 proteolytic complex. We found that iRhom2 loss suppressed the release of a group of transmembrane proteins, including known (e.g. CSF1R) and putative novel ADAM17 substrates. In the latter group, shedding of major histocompatibility complex class I molecules (MHC-I) was consistently reduced in both murine and human macrophages when iRhom2 was ablated. Intriguingly, it emerged that in addition to its shedding, iRhom2 could also control surface expression of MHC-I by an undefined mechanism. We have demonstrated the biological significance of this process by using an in vitro model of CD8+ T-cell (CTL) activation. In this model, iRhom2 loss and consequent reduction of MHC-I expression on the cell surface of an Epstein-Barr virus (EBV)-transformed lymphoblastoid cell line dampened activation of autologous CTLs and their cell-mediated cytotoxicity. Taken together, this study uncovers a new role for iRhom2 in controlling cell surface levels of MHC-I by a dual mechanism that involves regulation of their surface expression and ectodomain shedding.

Differential Protease Specificity by Collagenase as a Novel Approach to Serum Proteomics That Includes Identification of Extracellular Matrix Proteins without Enrichment

Circulating extracellular matrix (ECM) proteins are serological biomarkers of interest due to their association with pathologies involving disease processes such as fibrosis and cancers. In this study, we investigate the potential for serum biomarker research using differential protease specificity (DPS), leveraging alternate protease specificity as a targeting mechanism to selectively digest circulating ECM protein serum proteins. A proof-of-concept study is presented using serum from patients with cirrhotic liver or hepatocellular carcinoma. The approach uses collagenase DPS for digestion of deglycosylated serum and liquid-chromatography-trapped ion mobility-tandem mass spectrometry (LC-TIMS-MS/MS) to enhance the detection of ECM proteins in serum. It requires no sample enrichment and minimizes the albumin average precursor intensity readout to less than 1.2%. We further demonstrate the capabilities for using the method as a high-throughput matrix-assisted laser/desorption ionization mass spectrometry (MALDI-MS) assay coupled with reference library searching. A goal is to improve the depth and breadth of biofluid proteomics for noninvasive assays.

Vasorin promotes proliferation and migration via STAT3 signaling and acts as a promising therapeutic target of hepatocellular carcinoma

Abnormal expression of Vasorin (VASN) is related to many types of cancer, but the signaling pathway and mechanism of how VASN contributes to the carcinogenesis of hepatocellular carcinoma (HCC) are poorly understood. Here, we found that VASN was up-regulated in serum/serum exosome and tissues of HCC patients. The expression of VASN in serum improve the detection rate of HCC in alpha-fetoprotein-negative HCC patients. Immunohistochemistry revealed that VASN was highly expressed in HCC tissues and associated with different stages of HCC. Noticeably, when serum VASN combined with α-fetoprotein, the area under the curve (AUC), sensitivity, and specificity of HCC patients compared with healthy patients reached 0.918 (95% CI: 0.869-0.967, P < 0.001), 90.91%, and 90.20%, respectively. VASN knockout HCC cells were obtained by CRISPR/Cas9 and a VASN-specific monoclonal antibody was prepared by hybridoma technology. Knockout of VASN or the addition of VASN-specific monoclonal antibody suppressed the proliferation and migration of HCC. Mechanistically, VASN promote the proliferation and migration of HCC by regulating the phosphorylation of STAT3 and the expression of downstream genes CCND1 and MMP2. In conclusion, our findings suggest that VASN plays a crucial role in the activation of STAT3 signaling pathway in HCC, which is a promising target for the diagnosis and therapy of HCC.

Evidence for the expression of vasorin in the human female reproductive tissues

Objective: To investigate the expression and localization of Vasorin (Vasn) in human female reproductive system. Methods: The presence of Vasorin was evaluated by RT-PCR and immunoblotting analyses in patient-derived endometrial, myometrial and granulosa cells (GCs) primary cultures. Immunostaining analyses were performed to detect Vasn localization in primary cultures and in ovarian and uterine tissues. Results: Vasn mRNA was detected in patient-derived endometrial, myometrial and GCs primary cultures without significant differences at the transcript level. Otherwise, immunoblotting analysis showed that Vasn protein levels were significantly higher in GCs than proliferative endometrial stromal cells (ESCs) and myometrial cells. Immunohistochemistry performed in ovarian tissues revealed that Vasn was expressed in the GCs of ovarian follicles at different stages of development with a higher immunostaining signal in mature ovarian follicles such as the antral follicle or on the surface of cumulus oophorus cells than in early-stage follicles. The immunostaining of uterine tissues showed that Vasn was expressed in the proliferative stroma endometrium while it was significantly less expressed in the secretory endometrium. Conversely, no protein immunoreactivity was revealed in health myometrial tissue. Conclusions: Our results revealed the presence of Vasn in the ovary and the endometrium. The pattern of Vasn expression and distribution suggests that this protein may have a role in the regulation of processes such as folliculogenesis, oocyte maturation, and endometrial proliferation.

An ERK-dependent molecular switch antagonizes fibrosis and promotes regeneration in spiny mice (Acomys)

Although most mammals heal injured tissues and organs with scarring, spiny mice (Acomys) naturally regenerate skin and complex musculoskeletal tissues. Now, the core signaling pathways driving mammalian tissue regeneration are poorly characterized. Here, we show that, while immediate extracellular signal-regulated kinase (ERK) activation is a shared feature of scarring (Mus) and regenerating (Acomys) injuries, ERK activity is only sustained at high levels during complex tissue regeneration. Following ERK inhibition, ear punch regeneration in Acomys shifted toward fibrotic repair. Using single-cell RNA sequencing, we identified ERK-responsive cell types. Loss- and gain-of-function experiments prompted us to uncover fibroblast growth factor and ErbB signaling as upstream ERK regulators of regeneration. The ectopic activation of ERK in scar-prone injuries induced a pro-regenerative response, including cell proliferation, extracellular matrix remodeling, and hair follicle neogenesis. Our data detail an important distinction in ERK activity between regenerating and poorly regenerating adult mammals and open avenues to redirect fibrotic repair toward regenerative healing.

VASN promotes colorectal cancer progression by activating the YAP/TAZ and AKT signaling pathways via YAP

Colorectal cancer (CRC) is one of the most common gastrointestinal malignancies. Vasorin (VASN) has been reported to be critical in tumor development and angiogenesis. However, VASN has not been reported in CRC, and its role is unclear. In this study, VASN expression is upregulated in CRC compared with the normal tissues, and VASN expression positively correlates with N stage and poor overall survival by analysis of different datasets and 32 CRC clinicopathologic samples. Overexpression of VASN significantly promotes CRC cell progression, including proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT), while knockdown of VASN inhibits CRC progression. We found that VASN was associated with the YAP/TAZ and PI3K/AKT pathways by gene set enrichment analysis (GSEA) and gene ontology (GO) analysis. Notably, western blotting, immunofluorescence staining and co-immunofluorescence (co-IP) confirmed that VASN could interact with YAP and activate the YAP/TAZ and PTEN/PI3K/AKT pathways, and knockdown of YAP reversed this effect. Importantly, our findings indicate that VASN interacts with YAP to inhibit YAP phosphorylation and stimulates CRC proliferation, migration, and invasion through activation of the YAP/TAZ-TEAD target gene CTGF and PTEN/PI3K/AKT pathways. Our results also show that knockdown of YAP reverses the cellular phenotype induced by increased VASN. In conclusion, our study reveals that VASN acts as an oncogene to stimulate tumor progression in CRC, providing new insights into the molecular mechanisms of CRC development and representing a possible novel biomarker for CRC.

Effects of Physiological and Pathological Urea Concentrations on Human Microvascular Endothelial Cells

Urea is the uremic toxin accumulating with the highest concentration in the plasma of chronic kidney disease (CKD) patients, not being completely cleared by dialysis. Urea accumulation is reported to exert direct and indirect side effects on the gastrointestinal tract, kidneys, adipocytes, and cardiovascular system (CVS), although its pathogenicity is still questioned since studies evaluating its side effects lack homogeneity. Here, we investigated the effects of physiological and pathological urea concentrations on a human endothelial cell line from the microcirculation (Human Microvascular Endothelial Cells-1, HMEC-1). Urea (5 g/L) caused a reduction in the proliferation rate after 72 h of exposure and appeared to be a potential endothelial-to-mesenchymal transition (EndMT) stimulus. Moreover, urea induced actin filament rearrangement, a significant increase in matrix metalloproteinases 2 (MMP-2) expression in the medium, and a significant up- or down-regulation of other EndMT biomarkers (keratin, fibrillin-2, and collagen IV), as highlighted by differential proteomic analysis. Among proteins whose expression was found to be significantly dysregulated following exposure of HMEC-1 to urea, dimethylarginine dimethylaminohydrolase (DDAH) and vasorin turned out to be down-regulated. Both proteins have been directly linked to cardiovascular diseases (CVD) by in vitro and in vivo studies. Future experiments will be needed to deepen their role and investigate the signaling pathways in which they are involved to clarify the possible link between CKD and CVD.

SARS-CoV-2 Spike triggers barrier dysfunction and vascular leak via integrins and TGF-β signaling

Severe COVID-19 is associated with epithelial and endothelial barrier dysfunction within the lung as well as in distal organs. While it is appreciated that an exaggerated inflammatory response is associated with barrier dysfunction, the triggers of vascular leak are unclear. Here, we report that cell-intrinsic interactions between the Spike (S) glycoprotein of SARS-CoV-2 and epithelial/endothelial cells are sufficient to induce barrier dysfunction in vitro and vascular leak in vivo, independently of viral replication and the ACE2 receptor. We identify an S-triggered transcriptional response associated with extracellular matrix reorganization and TGF-β signaling. Using genetic knockouts and specific inhibitors, we demonstrate that glycosaminoglycans, integrins, and the TGF-β signaling axis are required for S-mediated barrier dysfunction. Notably, we show that SARS-CoV-2 infection caused leak in vivo, which was reduced by inhibiting integrins. Our findings offer mechanistic insight into SARS-CoV-2-triggered vascular leak, providing a starting point for development of therapies targeting COVID-19.

Immunomodulatory role of metalloproteinase ADAM17 in tumor development

ADAM17 is a member of the a disintegrin and metalloproteinase (ADAM) family of transmembrane proteases involved in the shedding of some cell membrane proteins and regulating various signaling pathways. More than 90 substrates are regulated by ADAM17, some of which are closely relevant to tumor formation and development. Besides, ADAM17 is also responsible for immune regulation and its substrate-mediated signal transduction. Recently, ADAM17 has been considered as a major target for the treatment of tumors and yet its immunomodulatory roles and mechanisms remain unclear. In this paper, we summarized the recent understanding of structure and several regulatory roles of ADAM17. Importantly, we highlighted the immunomodulatory roles of ADAM17 in tumor development, as well as small molecule inhibitors and monoclonal antibodies targeting ADAM17.

Vasorin plays a critical role in vascular smooth muscle cells and arterial functions

Within the cardiovascular system, the protein vasorin (Vasn) is predominantly expressed by vascular smooth muscle cells (VSMCs) in the coronary arteries and the aorta. Vasn knockout (Vasn^-/- ) mice die within 3 weeks of birth. In the present study, we investigated the role of vascular Vasn expression on vascular function. We used inducible Vasn knockout mice (Vasn^{CRE-ERT KO} and Vasn^{SMMHC-CRE-ERT2 KO} , in which respectively all cells or SMCs only are targeted) to analyze the consequences of total or selective Vasn loss on vascular function. Furthermore, in vivo effects were investigated in vitro using human VSMCs. The death of Vasn^{CRE-ERT KO} mice 21 days after tamoxifen injection was concomitant with decreases in blood pressure, angiotensin II levels, and vessel contractibility to phenylephrine. The Vasn^{SMMHC-CRE-ERT2 KO} mice displayed concomitant changes in vessel contractibility in response to phenylephrine and angiotensin II levels. In vitro, VASN deficiency was associated with a shift toward the SMC contractile phenotype, an increase in basal intracellular Ca²⁺ levels, and a decrease in the SMCs' ability to generate a calcium signal in response to carbachol or phenylephrine. Additionally, impaired endothelium-dependent relaxation (due to changes in nitric oxide signaling) was observed in all Vasn knockout mice models. Our present findings highlight the role played by Vasn SMC expression in the maintenance of vascular functions. The mechanistic experiments suggested that these effects are mediated by SMC phenotype switching and changes in intracellular calcium homeostasis, angiotensin II levels, and NO signaling.

The Autism Spectrum Disorder-Associated Bacterial Metabolite p-Cresol Derails the Neuroimmune Response of Microglial Cells Partially via Reduction of ADAM17 and ADAM10

The bacterial metabolite 4-methylphenol (para-cresol or p-cresol) and its derivative p-cresyl sulfate (pCS) are elevated in the urine and feces of children with autism spectrum disorder (ASD). It has been shown that p-cresol administration induces social behavior deficits and repetitive behavior in mice. However, the mechanisms of p-cresol, specifically its metabolite pCS that can reach the brain, in ASD remain to be investigated. The pCS has been shown to inhibit LPS-stimulated inflammatory response. A Disintegrin And Metalloprotease 10 (ADAM10) and A Disintegrin And Metalloprotease 17 (ADAM17) are thought to regulate microglial immune response by cleaving membrane-bound proteins. In the present study, a neuroinflammation model of LPS-activated BV2 microglia has been used to unveil the potential molecular mechanism of pCS in ASD pathogenesis. In microglial cells pCS treatment decreases the expression or maturation of ADAM10 and ADAM17. In addition, pCS treatment attenuates TNF-α and IL-6 releases as well as phagocytosis activity of microglia. In in vitro ADAM10/17 inhibition experiments, either ADAM10 or ADAM17 inhibition reduces constitutive and LPS-activated release of TNF-α, TNFR-1 and IL-6R by microglial cells, while it increases constitutive and LPS-activated microglial phagocytotic activity. The in vivo results further confirm the involvement of ADAM10 and ADAM17 in ASD pathogenesis. In in utero VPA-exposed male mice, elevated concentration in serum of p-cresol-associated metabolites pCS and p-cresyl glucuronide (pCG) is associated with a VPA-induced increased ADAM10 maturation, and a decreased ADAM17 maturation that is related with attenuated levels of soluble TNF-α and TGF-β1 in the mice brain. Overall, the present study demonstrates a partial role of ADAM10 and ADAM17 in the derailed innate immune response of microglial cells associated with pCS-induced ASD pathogenesis.

Vasorin Deletion in C57BL/6J Mice Induces Hepatocyte Autophagy through Glycogen-Mediated mTOR Regulation

Abnormal vasorin (Vasn) expression occurs in multiple diseases, particularly liver cancers. Vasn knockout (KO) in mice causes malnutrition, a shortened life span, and decreased physiological functions. However, the causes and underlying mechanisms remain unknown. Here, we established Vasn KO C57BL/6J mice by using the CRISPR/Cas9 system. The animals were weighed, and histology, immunohistochemistry, electronic microscopy, and liver function tests were used to examine any change in the livers. Autophagy markers were detected by Western blotting. MicroRNA (miRNA) sequencing was performed on liver samples and analyses to study the signaling pathway altered by Vasn KO. Significant reductions in mice body and liver weight, accompanied by abnormal liver function, liver injury, and reduced glycogen accumulation in hepatocytes, were observed in the Vasn KO mice. The deficiency of Vasn also significantly increased the number of autophagosomes and the expression of LC3A/B-II/I but decreased SQSTM1/p62 levels in hepatocytes, suggesting aberrant activation of autophagy. Vasn deficiency inhibited glycogen-mediated mammalian target of rapamycin (mTOR) phosphorylation and activated Unc-51-like kinase 1 (ULK1) signaling, suggesting that Vasn deletion upregulates hepatocyte autophagy through the mTOR-ULK1 signaling pathway as a possible cause of diminished life span and health. Our results indicate that Vasn is required for the homeostasis of liver glycogen metabolism upstream of hepatocyte autophagy, suggesting research values for regulating Vasn in pathways related to liver physiology and functions. Overall, this study provides new insight into the role of Vasn in liver functionality.

Vasorin contributes to lung injury via FABP4-mediated inflammation

BACKGROUND

Lung injury caused by pulmonary inflammation is one of the main manifestations of respiratory diseases. Vasorin (VASN) is a cell-surface glycoprotein encoded by the VASN gene and is expressed in the lungs of developing mouse foetuses. Previous research has revealed that VASN is associated with many diseases. However, its exact function in the lungs and the underlying mechanism remain poorly understood.

METHODS AND RESULTS

To investigate the molecular mechanisms involved in lung disease caused by VASN deficiency, a VASN gene knockout (VASN^-/-) model was established. The pathological changes in the lungs of VASN^-/- mice were similar to those in a lung injury experimental mouse model. We further analysed the transcriptomes of the lungs of VASN^-/- mice and wild-type mice. Genes in twenty-four signalling pathways were enriched in the lungs of VASN^-/- mice, among which PPAR signalling pathway genes (3 genes, FABP4, Plin1, AdipoQ, were upregulated, while apoA5 was downregulated) were found to be closely related to lung injury. The most significantly changed lung injury-related gene, FABP4, was selected for further verification. The mRNA and protein levels of FABP4 were significantly increased in the lungs of VASN^-/- mice, as were the mRNA and protein levels of the inflammatory factors IL-6, TNF-α and IL-1β.

CONCLUSIONS

We believe that these data provide molecular evidence for the regulatory role of VASN in inflammation in the context of lung injury.

Attenuation of Excess TNF-α Release in Crohn’s Disease by Silencing of iRHOMs 1/2 and the Restoration of TGF-β Mediated Immunosuppression Through Modulation of TACE Trafficking

TNFα converting enzyme (TACE) is a transmembrane metalloprotease that sheds an assortment of signaling receptors, cytokines, growth factors, and pro-inflammatory mediators. In Crohn’s disease (CD), TACE activity is upregulated, resulting in a marked increase of TNFα secretion and inflammation. Although treatment of CD with TNFα monoclonal antibodies is beneficial, many patients are at risk for acquiring opportunistic infections, and the treatment efficacy of TNFα monoclonal antibodies typically decreases over time. This study investigated an alternative approach for mitigating TNFα release by knocking down TACE membrane translocation in macrophages via inhibitory rhomboid proteins 1 and 2 (iRHOMs 1/2) siRNA treatment. First we measured TGFβRII shedding in ex vivo plasma samples collected from CD patients and healthy control subjects (N=40 per group). Then, we measured TGFβRII shedding and the expression and production of TGFβ ligand, TNFα, IL-6, IL-1β, IL-10, and total versus membranous TACE in vitro with THP-1 derived macrophage infected with Mycobacterium avium subspecies paratuberculosis (MAP), a highly studied CD-related pathogen. We determined that TGFβRII shedding was significantly higher in CD patients compared to healthy controls [515.52 ± 54.23 pg/mL vs 310.81 ± 43.16 pg/mL, respectively], and MAP-infected CD plasma samples had significantly more TGFβRII shedding (601.83 ± 49.56 pg/mL) than MAP-negative CD samples (430.37 ± 45.73 pg/mL). Moreover, we also determined that TACE production; TGFβ ligand expression and production; and TGFβRII shedding were also higher in MAP-infected THP-1 macrophages. Nevertheless, once we transfected the MAP infected macrophages with iRHOM siRNA, TACE production and membrane localization were significantly decreased, resulting in a significant decrease in TGFβRII shedding; an increase in Smad3 phosphorylation; a decrease in the expression and production of pro-inflammatory cytokines; and a decrease in the expression and production of stricture-associated factor, plasminogen activator inhibitor-1 (PAI-1). Our data clearly demonstrates that the regression of TACE trafficking, via iRHOM 1/2 silencing, significantly reduces the release of TNFα and restores the immunosuppressive capabilities of TGFβ signaling, which ultimately reverses inflammatory tissue damage. Accordingly, this study may provide a framework for the creation of newer, safer therapeutic options designed to treat inflammatory autoimmune diseases such as CD and rheumatoid arthritis.

Increased Complement-Associated Inflammation in Cytomegalovirus-Positive Hypertensive Anterior Uveitis Patients Based on the Aqueous Humor Proteomics Analysis

Herpetic anterior uveitis-associated ocular inflammation is commonly manifested with ocular hypertension and glaucoma. Relative to other viruses, cytomegalovirus (CMV) positive hypertensive anterior uveitis is associated with high recurrences of uveitis, as well as with uncontrolled intraocular pressure (IOP) and a subsequent higher requirement for future glaucoma surgery. To gain novel insights into the pathogenesis of ocular hypertension in these patients, we investigated the proteome changes of the aqueous humor (AH) derived from the CMV hypertensive anterior uveitis (CMV-HAU; n = 10) patients and non-glaucoma (cataract; n = 10) patients using liquid chromatography with tandem mass spectrometry. Among a total of 562 proteins identified, fifty and fifteen proteins were significantly elevated and decreased, respectively, in the AH of CMV-HAU patients compared to the control subjects by ≥2 fold. Gene ontology (GO) enrichment and network analyses of elevated proteins revealed that the enrichment of protein was involved in the complement activation, the humoral immune response mediated by the circulating immunoglobulins, proteolysis, and platelet degranulation. In the AH of CMV-HAU, GDF (growth/differentiation factor)-15, the inflammatory marker belonging to the TGF-β superfamily proteins, was significantly increased, while vasorin, an anti-TGF-β protein, levels were decreased. The trabecular meshwork cells infected with CMV exhibited a significantly increased expression of inflammatory markers. Collectively, these data indicate increased complement factor associated inflammation and humoral immunity in CMV-HAU associated ocular hypertension.

Application of Proteogenomics to Urine Analysis towards the Identification of Novel Biomarkers of Prostate Cancer: An Exploratory Study

Simple Summary

Prostate cancer (PCa) is one of the most common cancers. Due to the limited and invasive approaches for PCa diagnosis, it is crucial to identify more accurate and non-invasive biomarkers for its detection. The aim of our study was to non-invasively uncover new protein targets for detecting PCa using a proteomics and proteogenomics approach. This work identified several dysregulated mutant protein isoforms in urine from PCa patients, some of them predicted to have a protective or an adverse role in these patients. These results are promising given urine’s non-invasive nature and offers an auspicious opportunity for research and development of PCa biomarkers.

Abstract

To identify new protein targets for PCa detection, first, a shotgun discovery experiment was performed to characterize the urinary proteome of PCa patients. This revealed 18 differentially abundant urinary proteins in PCa patients. Second, selected targets were clinically tested by immunoblot, and the soluble E-cadherin fragment was detected for the first time in the urine of PCa patients. Third, the proteogenome landscape of these PCa patients was characterized, revealing 1665 mutant protein isoforms. Statistical analysis revealed 6 differentially abundant mutant protein isoforms in PCa patients. Analysis of the likely effects of mutations on protein function and PPIs involving the dysregulated mutant protein isoforms suggests a protective role of mutations HSPG2*Q1062H and VASN*R161Q and an adverse role of AMBP*A286G and CD55*S162L in PCa patients. This work originally characterized the urinary proteome, focusing on the proteogenome profile of PCa patients, which is usually overlooked in the analysis of PCa and body fluids. Combined analysis of mass spectrometry data using two different software packages was performed for the first time in the context of PCa, which increased the robustness of the data analysis. The application of proteogenomics to urine proteomic analysis can be very enriching in mutation-related diseases such as cancer.

Role of vasorin, an anti-apoptotic, anti-TGF-β and hypoxia-induced glycoprotein in the trabecular meshwork cells and glaucoma

Glaucoma, one of the leading causes of irreversible blindness, is commonly associated with elevated intraocular pressure due to impaired aqueous humour (AH) drainage through the trabecular meshwork. The aetiological mechanisms contributing to impaired AH outflow, however, are poorly understood. Here, we identified the secreted form of vasorin, a transmembrane glycoprotein, as a common constituent of human AH by mass spectrometry and immunoblotting analysis. ELISA assay revealed a significant but marginal decrease in vasorin levels in the AH of primary open‐angle glaucoma patients compared to non‐glaucoma cataract patients. Human trabecular meshwork (HTM) cells were confirmed to express vasorin, which has been shown to possess anti‐apoptotic and anti‐TGF‐β activities. Treatment of HTM cells with vasorin induced actin stress fibres and focal adhesions and suppressed TGF‐β2‐induced SMAD2/3 activation in HTM cells. Additionally, cobalt chloride‐induced hypoxia stimulated a robust elevation in vasorin expression, and vasorin suppressed TNF‐α‐induced cell death in HTM cells. Taken together, these findings reveal the importance of vasorin in maintenance of cell survival, inhibition of TGF‐β induced biological responses in TM cells, and the decreasing trend in vasorin levels in the AH of glaucoma patients suggests a plausible role for vasorin in the pathobiology of ocular hypertension and glaucoma.

The Utility of Serum Vasorin Levels as a Novel Potential Biomarker for Early Detection of Colon Cancer

Objective

The objective of this study was to investigate the utility of vasorin, a newly discovered transmembrane protein, as a novel biomarker in the early detection of colon cancer.

Methods

A total of 80 patients aged 55-70 years, diagnosed with colon cancer and followed up in our clinics, and 50 healthy volunteer blood donors were included in the study. Participants' demographics such as age, gender, and vasorin levels were recorded and compared between the patient and control groups. In addition, primary tumor status (pT) values N and T stages of the tumors were studied in the patient group. All patients included in the study were pathologically confirmed by colonoscopy plus biopsy and postoperative histopathologic examination.

Results

The mean age was found as 64.59±3.70 (min-max: 55-70) years old in the patient group and 63.56±3.07 (min-max: 57-70) years. There was no statistically significant difference between both groups regarding demographics (p>0.05). Serum Vasorin levels were higher in patients with colon cancer than in the control group (p<0.001). Serum Vasorin levels were higher among patients with advanced disease and related to the clinical stage of the locally advanced tumor. 

Conclusion

Our findings revealed that serum vasorin levels are upregulated in patients with colon cancer. Raised vasorin levels may be a non-invasive biomarker beneficial for early detection and prediction of colon cancer prognosis. In addition, vasorin levels further rose as the disease advanced to higher TNM (tumor (T), nodes (N), and metastases (M)) stages. Further comprehensive studies are needed to draw more evident conclusions and generalize our results.

SARS-CoV-2 Spike triggers barrier dysfunction and vascular leak via integrins and TGF-β signaling

Severe COVID-19 is associated with epithelial and endothelial barrier dysfunction within the lung as well as in distal organs. While it is appreciated that an exaggerated inflammatory response is associated with barrier dysfunction, the triggers of this pathology are unclear. Here, we report that cell-intrinsic interactions between the Spike (S) glycoprotein of SARS-CoV-2 and epithelial/endothelial cells are sufficient to trigger barrier dysfunction in vitro and vascular leak in vivo , independently of viral replication and the ACE2 receptor. We identify an S-triggered transcriptional response associated with extracellular matrix reorganization and TGF-β signaling. Using genetic knockouts and specific inhibitors, we demonstrate that glycosaminoglycans, integrins, and the TGF-β signaling axis are required for S-mediated barrier dysfunction. Our findings suggest that S interactions with barrier cells are a contributing factor to COVID-19 disease severity and offer mechanistic insight into SARS-CoV-2 triggered vascular leak, providing a starting point for development of therapies targeting COVID-19 pathogenesis.

ADAM 17 and Epithelial-to-Mesenchymal Transition: The Evolving Story and Its Link to Fibrosis and Cancer

For decades, metalloproteinase 17 (ADAM17) has been the goal of wide investigation. Since its discovery as the tumour necrosis factor-α convertase, it has been studied as the main drug target, especially in the context of inflammatory conditions and tumour. In fact, evidence is mounting to support a key role of ADAM17 in the induction of the proliferation, migration and progression of tumour cells and the trigger of the pro-fibrotic process during chronic inflammatory conditions; this occurs, probably, through the activation of epithelial-to-mesenchymal transition (EMT). EMT is a central morphologic conversion that occurs in adults during wound healing, tumour progression and organ fibrosis. EMT is characterised by the disassembly of cell–cell contacts, remodelling of the actin cytoskeleton and separation of cells, and generates fibroblast-like cells that express mesenchymal markers and have migratory properties. This transition is characterised by loss of epithelial proteins such as E-cadherin and the acquisition of new mesenchymal markers, including vimentin and a-smooth muscle actin. The present review discusses the current understanding of molecular mechanisms involved in ADAM17-dependent EMT in order to individuate innovative therapeutic strategies using ADAM17-related pathways.

Contribution of ADAM17 and related ADAMs in cardiovascular diseases

A disintegrin and metalloproteases (ADAMs) are key mediators of cell signaling by ectodomain shedding of various growth factors, cytokines, receptors and adhesion molecules at the cellular membrane. ADAMs regulate cell proliferation, cell growth, inflammation, and other regular cellular processes. ADAM17, the most extensively studied ADAM family member, is also known as tumor necrosis factor (TNF)-α converting enzyme (TACE). ADAMs-mediated shedding of cytokines such as TNF-α orchestrates immune system or inflammatory cascades and ADAMs-mediated shedding of growth factors causes cell growth or proliferation by transactivation of the growth factor receptors including epidermal growth factor receptor. Therefore, increased ADAMs-mediated shedding can induce inflammation, tissue remodeling and dysfunction associated with various cardiovascular diseases such as hypertension and atherosclerosis, and ADAMs can be a potential therapeutic target in these diseases. In this review, we focus on the role of ADAMs in cardiovascular pathophysiology and cardiovascular diseases. The main aim of this review is to stimulate new interest in this area by highlighting remarkable evidence.

Difference in potential DNA methylation impact on gene expression between fast- and slow-type myofibers

Skeletal muscles are comprised of two major types of myofibers, fast and slow. It is hypothesized that once myofiber type is determined, muscle fiber-type specificity is maintained by an epigenetic mechanism, however, this remains poorly understood. To address this, we conducted a comprehensive CpG methylation analysis with a reduced representation of bisulfite sequencing (RRBS). Using GFP-myh7 mouse, we visually distinguished and separately pooled slow-type and myh7-negative fast-type fibers for analyses. A total of 31,967 and 26,274 CpGs were hypermethylated by ≥10% difference in the fast- and slow-type fibers, respectively. Notably, the number of promoter-hypermethylated genes with downregulated expression in the slow-type fibers was 3.5 times higher than that in the fast-type fibers. Gene bodies of the fast-type-specific myofibrillar genes Actn3, Tnnt3, Tnni2, Tnnc2, and Tpm1 were hypermethylated in the slow-type fibers, whereas those of the slow-type-specific genes Myh7, Tnnt1, and Tpm3 were hypermethylated in the fast-type fibers. Each of the instances of gene hypermethylation was associated with the respective downregulated expression. In particular, a relationship between CpG methylation sites and the transcription variant distribution of Tpm1 was observed, suggesting a regulation of Tpm1 alternative promoter usage by gene body CpG methylation. An association of hypermethylation with the regulation of gene expression was also observed in the transcription factors Sim2 and Tbx1. These results suggest not only a myofiber type-specific regulation of gene expression and alternative promoter usage by gene body CpG methylation but also a dominant effect of promoter-hypermethylation on the gene expressions in slow myofibers.

Uncovering the secretome of mesenchymal stromal cells exposed to healthy, traumatic, and degenerative intervertebral discs: a proteomic analysis

BACKGROUND

Mesenchymal stromal cells (MSCs) have been introduced as promising cell source for regenerative medicine. Besides their multilineage differentiation capacity, MSCs release a wide spectrum of bioactive factors. This secretome holds immunomodulatory and regenerative capacities. In intervertebral disc (IVD) cells, application of MSC secretome has been shown to decrease the apoptosis rate, induce proliferation, and promote production of extracellular matrix (ECM). For clinical translation of secretome-based treatment, characterization of the secretome composition is needed to better understand the induced biological processes and identify potentially effective secretomes.

METHODS

This study aimed to investigate the proteome released by bone marrow-derived MSCs following exposure to a healthy, traumatic, or degenerative human IVD environment by mass spectroscopy and quantitative immunoassay analyses. Exposure of MSCs to the proinflammatory stimulus interleukin 1β (IL-1β) was used as control.

RESULTS

Compared to MSC baseline secretome, there were 224 significantly up- or downregulated proteins following healthy, 179 following traumatic, 223 following degenerative IVD, and 160 proteins following IL-1β stimulus. Stimulation of MSCs with IVD conditioned media induced a more complex MSC secretome, involving more biological processes, compared to stimulation with IL-1β. The MSC response to stimulation with IVD conditioned medium was dependent on their pathological status.

CONCLUSIONS

The MSC secretome seemed to match the primary need of the IVD: homeostasis maintenance in the case of healthy IVDs, versus immunomodulation, adjustment of ECM synthesis and degradation disbalance, and ECM (re) organization in the case of traumatic and degenerative IVDs. These findings highlight the importance of cell preconditioning in the development of tailored secretome therapies. The secretome of human bone marrow-derived mesenchymal stromal cells (MSCs) stimulated with intervertebral disc (IVD) conditioned medium was analyzed by proteomic profiling. Depending on the pathological state of the IVD, the MSC secretome protein composition indicated immunomodulatory or anabolic activity of the secretome. These findings may have implications for tailored secretome therapy for the IVD and other tissues.

The Gut-Brain Axis in Autism Spectrum Disorder: A Focus on the Metalloproteases ADAM10 and ADAM17

Autism Spectrum Disorder (ASD) is a spectrum of disorders that are characterized by problems in social interaction and repetitive behavior. The disease is thought to develop from changes in brain development at an early age, although the exact mechanisms are not known yet. In addition, a significant number of people with ASD develop problems in the intestinal tract. A Disintegrin And Metalloproteases (ADAMs) include a group of enzymes that are able to cleave membrane-bound proteins. ADAM10 and ADAM17 are two members of this family that are able to cleave protein substrates involved in ASD pathogenesis, such as specific proteins important for synapse formation, axon signaling and neuroinflammation. All these pathological mechanisms are involved in ASD. Besides the brain, ADAM10 and ADAM17 are also highly expressed in the intestines. ADAM10 and ADAM17 have implications in pathways that regulate gut permeability, homeostasis and inflammation. These metalloproteases might be involved in microbiota-gut-brain axis interactions in ASD through the regulation of immune and inflammatory responses in the intestinal tract. In this review, the potential roles of ADAM10 and ADAM17 in the pathology of ASD and as targets for new therapies will be discussed, with a focus on the gut-brain axis.

Targeting Notch in oncology: the path forward

Notch signalling is involved in many aspects of cancer biology, including angiogenesis, tumour immunity and the maintenance of cancer stem-like cells. In addition, Notch can function as an oncogene and a tumour suppressor in different cancers and in different cell populations within the same tumour. Despite promising preclinical results and early-phase clinical trials, the goal of developing safe, effective, tumour-selective Notch-targeting agents for clinical use remains elusive. However, our continually improving understanding of Notch signalling in specific cancers, individual cancer cases and different cell populations, as well as crosstalk between pathways, is aiding the discovery and development of novel investigational Notch-targeted therapeutics.

TGF-β Induced CTGF Expression in Human Lung Epithelial Cells through ERK, ADAM17, RSK1, and C/EBPβ Pathways

Background: Lung epithelial cells play critical roles in idiopathic pulmonary fibrosis. Methods: In the present study, we investigated whether transforming growth factor-β (TGF-β)-induced expression of connective tissue growth factor (CTGF) was regulated by the extracellular signal-regulated kinase (ERK)/a disintegrin and metalloproteinase 17 (ADAM17)/ribosomal S6 kinases 1 (RSK1)/CCAAT/enhancer-binding protein β (C/EBPβ) signaling pathway in human lung epithelial cells (A549). Results: Our results revealed that TGF-β-induced CTGF expression was weakened by ADAM17 small interfering RNA (ADAM17 siRNA), TNF-α processing inhibitor-0 (TAPI-0, an ADAM17 inhibitor), U0126 (an ERK inhibitor), RSK1 siRNA, and C/EBPβ siRNA. TGF-β-induced ERK phosphorylation as well as ADAM17 phosphorylation was attenuated by U0126. The TGF-β-induced increase in RSK1 phosphorylation was inhibited by TAPI-0 and U0126. TGF-β-induced C/EBPβ phosphorylation was weakened by U0126, ADAM17 siRNA, and RSK1 siRNA. In addition, TGF-β increased the recruitment of C/EBPβ to the CTGF promoter. Furthermore, TGF-β enhanced fibronectin (FN), an epithelial–mesenchymal transition (EMT) marker, and CTGF mRNA levels and reduced E-cadherin mRNA levels. Moreover, TGF-β-stimulated FN protein expression was reduced by ADAM17 siRNA and CTGF siRNA. Conclusion: The results suggested that TGF-β induces CTGF expression through the ERK/ADAM17/RSK1/C/EBPβ signaling pathway. Moreover, ADAM17 and CTGF participate in TGF-β-induced FN expression in human lung epithelial cells.

Comparative Secretomics Gives Access to High Confident Secretome Data: Evaluation of Different Methods for the Determination of Bona Fide Secreted Proteins

Secretome analysis is broadly applied to understand the interplay between cells and their microenvironment. In particular, the unbiased analysis by mass spectrometry-based proteomics of conditioned medium has been successfully applied. In this context, several approaches have been developed allowing to distinguish proteins actively secreted by cells from proteins derived from culture medium or proteins released from dying cells. Here, three different methods comparing conditioned medium and lysate by quantitative mass spectrometry-based proteomics to identify bona fide secreted proteins are evaluated. Evaluation in three different human cell lines reveals that all three methods give access to a similar set of bona fide secreted proteins covering a broad abundance range. In the analyzed primary cells, that is, mesenchymal stromal cells and normal human dermal fibroblasts, more than 70% of the identified proteins are linked to classical secretion pathways. Furthermore, 4-12% are predicted to be released by unconventional secretion pathways. Interestingly, evidence of release by ectodomain shedding in a large number of the remaining candidate proteins is found. In summary, it is convinced that comparative secretomics is currently the method of choice to obtain high-confident secretome data and to identify novel candidates for unconventional protein secretion which have been neglected so far.

Protease Activity Profiling via Programmable Phage Display of Comprehensive Proteome-Scale Peptide Libraries

Endopeptidases catalyze the internal cleavage of proteins, playing pivotal roles in protein turnover, substrate maturation, and the activation of signaling cascades. A broad range of biological functions in health and disease are controlled by proteases, yet assays to characterize their activities at a proteomic scale do not exist. To address this unmet need, we developed Sensing EndoPeptidase Activity via Release and recapture using flAnking Tag Epitopes (SEPARATE), which uses a monovalent phage display of the human proteome at a 90-aa peptide resolution. We demonstrate that SEPARATE is compatible with several human proteases from distinct catalytic classes, including caspase-1, ADAM17, and thrombin. Both well-characterized and newly identified substrates of these enzymes were detected in the assay. SEPARATE was used to discover a non-canonical caspase-1 substrate, the E3 ubiquitin ligase HUWE1, a key mediator of apoptotic cell death. SEPARATE enables efficient, unbiased assessment of endopeptidase activity by using a phage-displayed proteome. A record of this paper's Transparent Peer Review process is included in the Supplemental Information.

Vasorin/ATIA Promotes Cigarette Smoke-Induced Transformation of Human Bronchial Epithelial Cells by Suppressing Autophagy-Mediated Apoptosis

BACKGROUND

Escaping cell death pathways is an important event during carcinogenesis. We previously identified anti-TNFα-induced apoptosis (ATIA, also known as vasorin) as an antiapoptotic factor that suppresses reactive oxygen species (ROS) production. However, the role of vasorin in lung carcinogenesis has not been investigated.

METHODS

Vasorin expression was examined in human lung cancer tissues with immunohistochemistry and database analysis. Genetic and pharmacological approaches were used to manipulate protein expression and autophagy activity in human bronchial epithelial cells (HBECs). ROS generation was measured with fluorescent indicator, apoptosis with release of lactate dehydrogenase, and cell transformation was assessed with colony formation in soft agar.

RESULTS

Vasorin expression was increased in human lung cancer tissues and cell lines, which was inversely associated with lung cancer patient survival. Cigarette smoke extract (CSE) and benzo[a]pyrene diol epoxide (BPDE)-induced vasorin expression in HBECs. Vasorin knockdown in HBECs significantly suppressed CSE-induced transformation in association with enhanced ROS accumulation and autophagy. Scavenging ROS attenuated autophagy and cytotoxicity in vasorin knockdown cells, suggesting that vasorin potentiates transformation by impeding ROS-mediated CSE cytotoxicity and improving survival of the premalignant cells. Suppression of autophagy effectively inhibited CSE-induced apoptosis, suggesting that autophagy was pro-apoptotic in CSE-treated cells. Importantly, blocking autophagy strongly potentiated CSE-induced transformation.

CONCLUSION

These results suggest that vasorin is a potential lung cancer-promoting factor that facilitates cigarette smoke-induced bronchial epithelial cell transformation by suppressing autophagy-mediated apoptosis, which could be exploited for lung cancer prevention.

Bone secreted factors induce cellular quiescence in prostate cancer cells

Disseminated tumor cells (DTCs) undergo a dormant state in the distant metastatic site(s) before becoming overt metastatic diseases. In prostate cancer (PCa), bone metastasis can occur years after prostatectomy, suggesting that bone may provide dormancy-inducing factors. To search for these factors, we prepared conditioned media (CM) from calvariae. Using live-cell imaging, we found that Calvarial-CM treatment increased cellular quiescence in C4-2B4 PCa cells. Mass spectrometry analysis of Calvarial-CM identified 132 secreted factors. Western blot and ELISA analyses confirmed the presence of several factors, including DKK3, BMP1, neogenin and vasorin in the Calvarial-CM. qRT-PCR analysis of total calvariae versus isolated osteoblasts showed that DKK3, BMP1, vasorin and neogenin are mainly expressed by osteoblasts, while MIA, LECT1, NGAL and PEDF are expressed by other calvarial cells. Recombinant human DKK3, BMP1, vasorin, neogenin, MIA and NGAL treatment increased cellular quiescence in both C4-2b and C4-2B4 PCa cells. Mechanistically, DKK3, vasorin and neogenin, but not BMP1, increased dormancy through activating the p38MAPK signaling pathway. Consistently, DKK3, vasorin and neogenin failed to induce dormancy in cells expressing dominant-negative p38αMAPK while BMP1 remained active, suggesting that BMP1 uses an alternative dormancy signaling pathway. Thus, bone secretes multiple dormancy-inducing factors that employ distinct signaling pathways to induce DTC dormancy in bone.

Inhibition of vascular smooth muscle cell calcification by vasorin through interference with TGFβ1 signaling

Elevated transforming growth factor β1 (TGFβ1) levels are frequently observed in chronic kidney disease (CKD) patients. TGFβ1 contributes to development of medial vascular calcification during hyperphosphatemia, a pathological process promoted by osteo-/chondrogenic transdifferentiation of vascular smooth muscle cells (VSMCs). Vasorin is a transmembrane glycoprotein highly expressed in VSMCs, which is able to bind TGFβ to inhibit TGFβ signaling. Thus, the present study explored the effects of vasorin on osteo-/chondrogenic transdifferentiation and calcification of VSMCs. Primary human aortic smooth muscle cells (HAoSMCs) were treated with recombinant human TGFβ1 or β-glycerophosphate without or with recombinant human vasorin or vasorin gene silencing by siRNA. As a result, TGFβ1 down-regulated vasorin mRNA expression in HAoSMCs. Vasorin supplementation inhibited TGFβ1-induced pathway activation, SMAD2 phosphorylation and downstream target genes expression in HAoSMCs. Furthermore, treatment with exogenous vasorin blunted, while vasorin knockdown augmented TGFβ1-induced osteo-/chondrogenic transdifferentiation of HAoSMCs. In addition, phosphate down-regulated vasorin mRNA expression in HAoSMCs. Phosphate-induced TGFβ1 expression was not affected by addition of exogenous vasorin. Nonetheless, the phosphate-induced TGFβ1 signaling, osteo-/chondrogenic transdifferentiation and calcification of HAoSMCs were all blunted by vasorin. Conversely, silencing of vasorin aggravated osteoinduction in HAoSMCs during high phosphate conditions. Aortic vasorin expression was reduced in the hyperphosphatemic klotho-hypomorphic mouse model of CKD-related vascular calcification. In conclusion, vasorin, which suppresses TGFβ1 signaling and protects against osteo-/chondrogenic transdifferentiation and calcification of VSMCs, is reduced by pro-calcifying conditions. Thus, vasorin is a novel key regulator of VSMC calcification and may represent a potential therapeutic target for vascular calcification during CKD.

Mesenchymal transition and increased therapy resistance of glioblastoma cells is related to astrocyte reactivity

Grade IV astrocytoma/glioblastoma multiforme (GBM) is essentially incurable, partly due to its heterogenous nature, demonstrated even within the glioma-initiating cell (GIC) population. Increased therapy resistance of GICs is coupled to transition into a mesenchymal (MES) cell state. The GBM MES molecular signature displays a pronounced inflammatory character and its expression vary within and between tumors. Herein, we investigate how MES transition of GBM cells relates to inflammatory responses of normal astroglia. In response to CNS insults astrocytes enter a reactive cell state and participate in directing neuroinflammation and subsequent healing processes. We found that the MES signature show strong resemblance to gene programs induced in reactive astrocytes. Likewise, astrocyte reactivity gene signatures were enriched in therapy-resistant MES-like GIC clones. Variable expression of astrocyte reactivity related genes also largely defined intratumoral GBM cell heterogeneity at the single-cell level and strongly correlated with our previously defined therapy-resistance signature (based on linked molecular and functional characterization of GIC clones). In line with this, therapy-resistant MES-like GIC secreted immunoregulatory and tissue repair related proteins characteristic of astrocyte reactivity. Moreover, sensitive GIC clones could be made reactive through long-term exposure to the proinflammatory cytokine interleukin 1 beta (IL1β). IL1β induced a slow MES transition, increased therapy resistance, and a shift in DNA methylation profile towards that of resistant clones, which confirmed a slow reprogramming process. In summary, GICs enter through MES transition a reactive-astrocyte-like cell state, connected to therapy resistance. Thus, from a biological point of view, MES GICs would preferably be called 'reactive GICs'. The ability of GBM cells to mimic astroglial reactivity contextualizes the immunomodulatory and microenvironment reshaping abilities of GBM cells that generate a tumor-promoting milieu. This insight will be important to guide the development of future sensitizing therapies targeting treatment-resistant relapse-driving cell populations as well as enhancing the efficiency of immunotherapies in GBM. © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Vasorin stimulates malignant progression and angiogenesis in glioma

Glioma, the most common human primary brain tumor, is characterized by invasive capabilities and angiogenesis. Vasorin (VASN), a transmembrane protein, is reported to be associated with vascular injury repair and is overexpressed in some human tumors. However, its role in tumor progression and angiogenesis in glioma is unknown. In this study, VASN was shown to be overexpressed in high‐grade gliomas, and the expression level correlated with tumor grade and microvessel density in glioma specimens. Glioma patients with high VASN expression had a shorter overall survival time. Knockdown of VASN in glioma cells by shRNA significantly inhibited the malignancy of glioma, including cell proliferation, colony formation, invasion, and sphere formation. Ectopic expression of VASN increased glioma progression in vitro. The expression of VASN correlated with the mesenchymal type of glioblastoma multiforme (GBM) subtyped by gene set enrichment analysis (GSEA). Our results showed that the concentration of VASN was increased in the conditioned medium (CM) from glioma cells with VASN overexpression, and the CM from glioma cells with knockdown or overexpressed VASN inhibited or promoted HUVEC migration and tubulogenesis in vitro, respectively. Glioma growth and angiogenesis were stimulated upon ectopic expression of VASN in vivo. The STAT3 and NOTCH pathways were found to be activated and inhibited by VASN overexpression. Our findings suggest that VASN stimulates tumor progression and angiogenesis in glioma, and, as such, represents a novel therapeutic target for glioma.

Identification of key genes relevant to the prognosis of ER-positive and ER-negative breast cancer based on a prognostic prediction system

Few prognostic indicators with differential expression have been reported among the differing ER statuses. We aimed to screen important breast cancer prognostic genes related to ER status and to construct an efficient prognostic prediction system. mRNA expression profiles were downloaded from TCGA and GSE70947 dataset. Two hundred seventy-one overlapping differentially expressed genes (DEGs) between the ER- and ER+ breast cancer samples were identified. Among the 271 DEGs, 109 prognostically relevant mRNAs were screened. mRNAs such as RASEF, ITM2C, CPEB2, ESR1, ANXA9, and VASN correlated strongly with breast cancer prognosis. Three modules, which contained 28, 9 and 8 enriched DEGs, were obtained from the network, and the DEGs in these modules were enriched in response to hormone stimulus, epithelial cell development, and host cell entry. Using bayes discriminant analysis, 48 signature genes were screened. We constructed a prognostic prediction system using the 48 signature genes and validated this system as relatively accurate and reliable. The DEGs might be closely associated with the prognosis in patients with breast cancer. We validated the effectiveness of our prognostic prediction system by GEO database. Therefore, this system might be a useful tool for preliminary screening and validation of potential prognosis indicators for ER+ breast cancer derived from mechanistic research.

Secretome analysis of human bone marrow derived mesenchymal stromal cells

As an essential cellular component of the bone marrow (BM) microenvironment mesenchymal stromal cells (MSC) play a pivotal role for the physiological regulation of hematopoiesis, in particular through the secretion of cytokines and chemokines. Mass spectrometry (MS) facilitates the identification and quantification of a large amount of secreted proteins (secretome), but can be hampered by the false-positive identification of contaminating proteins released from dead cells or derived from cell medium. To reduce the likelihood of contaminations we applied an approach combining secretome and proteome analysis to characterize the physiological secretome of BM derived human MSC. Our analysis revealed a secretome consisting of 315 proteins. Pathway analyses of these proteins revealed a high abundance of proteins related to cell growth and/or maintenance, signal transduction and cell communication thereby representing key biological functions of BM derived MSC on protein level. Within the MSC secretome we identified several cytokines and growth factors such as VEGFC, TGF-β1, TGF-β2 and GDF6 which are known to be involved in the physiological regulation of hematopoiesis. By comparing the peptide patterns of secretomes and cell lysates 17 proteins were identified as candidates for proteolytic processing. Taken together, our combined MS work-flow reduced the likelihood of contaminations and enabled us to carve out a specific overview about the composition of the secretome from human BM derived MSC. This methodological approach and the specific secretome signature of BM derived MSC may serve as basis for future comparative analyses of the interplay of MSC and HSPC in patients with hematological malignancies.

Sialylation of vasorin by ST3Gal1 facilitates TGF-β1-mediated tumor angiogenesis and progression

ST3Gal1 is a key sialyltransferase which adds α2,3‐linked sialic acid to substrates and generates core 1 O‐glycan structure. Upregulation of ST3Gal1 has been associated with worse prognosis of breast cancer patients. However, the protein substrates of ST3Gal1 implicated in tumor progression remain elusive. In our study, we demonstrated that ST3GAL1‐silencing significantly reduced tumor growth along with a notable decrease in vascularity of MCF7 xenograft tumors. We identified vasorin (VASN) which was shown to bind TGF‐β1, as a potential candidate that links ST3Gal1 to angiogenesis. LC‐MS/MS analysis of VASN secreted from MCF7, revealed that more than 80% of its O‐glycans are sialyl‐3T and disialyl‐T. ST3GAL1‐silencing or desialylation of VASN by neuraminidase enhanced its binding to TGF‐β1 by 2‐ to 3‐fold and thereby dampening TGF‐β1 signaling and angiogenesis, as indicated by impaired tube formation of HUVECs, suppressed angiogenesis gene expression and reduced activation of Smad2 and Smad3 in HUVEC cells. Examination of 114 fresh primary breast cancer and their adjacent normal tissues showed that the expression levels of ST3Gal1 and TGFB1 were high in tumor part and the expression of two genes was positively correlated. Kaplan Meier survival analysis showed a significantly shorter relapse‐free survival for those with lower expression VASN, notably, the combination of low VASN with high ST3GAL1 yielded even higher risk of recurrence (p = 0.025, HR = 2.967, 95% CI = 1.14–7.67). Since TGF‐β1 is known to transcriptionally activate ST3Gal1, our findings illustrated a feedback regulatory loop in which TGF‐β1 upregulates ST3Gal1 to circumvent the negative impact of VASN.

What's new?

The addition of sialic acid to glycoproteins is dysregulated in many cancers, and enhanced expression of one key enzyme, the sialyltransferase ST3Gal1, is associated with poor prognosis. Here, the authors identified the membrane protein vasorin as a new ST3Gal1 substrate and connect it with TGF‐β1‐induced signaling and angiogenesis in breast cancer. As silencing of ST3Gal1 dampened TGF‐β1 signaling and suppressed angiogenesis, development of ST3Gal1 inhibitors might be clinically useful to improve the prognosis of breast cancer patients.

From Vascular Smooth Muscle Cells to Folliculogenesis: What About Vasorin?

First described in 1988, vasorin (VASN) is a transmembrane glycoprotein expressed during early mouse development, and with a less extent, in various organs and tissues (e.g., kidney, aorta, and brain) postnatally. Vasn KO mice die after 3 weeks of life from unknown cause(s). No human disease has been associated with variants of this gene so far, but VASN seems to be a potential biomarker for nephropathies and tumorigenesis. Its interactions with the TGF-β and Notch1 pathways offer the most serious assumptions regarding VASN functions. In this review, we will describe current knowledge about this glycoprotein and discuss its implication in various organ pathophysiology.

Reduced vasorin enhances angiotensin II signaling within the aging arterial wall

The glycosylated protein vasorin physically interacts with the transforming growth factor-beta1 (TGF-β1) and functionally attenuates its fibrogenic signaling in the vascular smooth muscle cells (VSMCs) of the arterial wall. Angiotensin II (Ang II) amplifies TGF-β1 activation in the VSMCs of the arterial wall with aging. In this study, we hypothesized that a reduced expression of the protein vasorin plays a contributory role in magnifying Ang II-associated fibrogenic signaling in the VSMCs of the arterial wall with aging. The current study shows that vasorin mRNA and protein expression were significantly decreased both in aortic wall and VSMCs from old (30 mo) vs. young (8 mo) FXBN rats. Exposing young VSMCs to Ang II reduced vasorin protein expression to the levels of old untreated cells while treating old VSMCs with the Ang II type AT1 receptor antagonist Losartan upregulated vasorin protein expression up to the levels of young. The physical interaction between vasorin and TGF-β1 was significantly decreased in old vs. young VSMCs. Further, exposing young VSMCs to Ang II increased the levels of matrix metalloproteinase type II (MMP-2) activation and TGF-β1 downstream molecules p-SMAD-2/3 and collagen type I production up to the levels of old untreated VSMCs, and these effects were substantially inhibited by overexpressing vasorin. Administration of Ang II to young rats (8 mo) for 28 days via an osmotic minipump markedly reduced the expression of vasorin. Importantly, vasorin protein was effectively cleaved by activated MMP-2 both in vitro and in vivo. Administration of the MMP inhibitor, PD 166793, for 6 mo to young adult (18 mo) via a daily gavage markedly increased levels of vasorin in the aortic wall. Thus, reduced vasorin amplifies Ang II profibrotic signaling via an activation of MMP-2 in VSMCs within the aging arterial wall.

Vasorin: a newly identified regulator of ovarian folliculogenesis

Members of the TGF-β superfamily take part in the control of folliculogenesis. Vasorin (Vasn) is a newly identified negative regulator of TGF-β signaling whose possible involvement in ovarian physiology has never been studied. Here, we demonstrate that Vasn is expressed in the ovary by somatic cells of follicles, and that its expression is up-regulated by LH. We established a conditional knockout (cKO) mouse model in which Vasn is deleted specifically in granulosa cells of growing follicles from the secondary stage onwards. Using this model, we show that, upon hormonal stimulation, follicle ovulation size is almost 2-fold higher. This enhanced ovulatory response is associated with overactivation of the TGF-β signaling pathway and a lower number of atretic antral follicles. Of importance, we demonstrate that the number of primordial follicles is reduced in prepubertal cKO mouse ovaries, which suggests that the production of VASN by growing follicles protects the ovarian reserve. Finally, analysis of systemic KO mice revealed that the ovarian reserve is almost 2.5-fold higher, which implies that Vasn may also play a role in primordial follicle formation. Overall, our findings reveal that Vasn is a new regulator that exerts an effect on several key ovarian functions, including folliculogenesis, maintenance of the ovarian reserve, and ovulation.-Rimon-Dahari, N., Heinemann-Yerushalmi, L., Hadas, R., Kalich-Philosoph, L., Ketter, D., Nevo, N., Galiani, D., Dekel, N. Vasorin: a newly identified regulator of ovarian folliculogenesis.

Identification of Functional mimotopes of human Vasorin Ectodomain by Biopanning

Human vasorin (VASN) as a type I transmembrane protein, is a potential biomarker of hepatocellular carcinoma, which could expedite HepG2 cell proliferation and migration significantly in vitro. The ectodomain of VASN was proteolytically released to generate soluble VASN (sVASN), which was validated to be the active form. Among several monoclonal antibodies produced against sVASN, the clone V21 was found to bind with the recombinant human sVASN (rhsVASN) with the highest affinity and specificity, and also have inhibitory effects on proliferation and migration of HepG2 cells. Hence the phage-displayed peptide library was screened against the antibody V21. The positive phage clones were isolated and sequenced, and one unique consensus motifs was obtained. The result of sequence alignment showed that the conserved motif had similarity to VASN(Cys432-Cys441), embedded in the epidermal growth factor (EGF)-like domain. The synthetic mimotope peptide V21P1 and V21P2 were confirmed to bind with V21 and could compete with rhsVASN in ELISA assay. And they could also almost completely reverse the inhibitory effect of V21 on HepG2 migration and proliferation. Furthermore, the antibodies produced against V21P1 were able to bind not only with the peptide V21P1, but also with rhsVASN and the natural VASN from HepG2 cell. Our results showed that V21 seemed to be a functional antibody. The mimotopes toward V21 might mimic the functional domain of VASN, which would be helpful to exploit VASN functions and act as a candidate target for developing therapeutic antibodies against VASN.

Tumor-Suppressor Inactivation of GDF11 Occurs by Precursor Sequestration in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is an aggressive and heterogeneous carcinoma in which various tumor-suppressor genes are lost by mutation, deletion, or silencing. Here we report a tumor-suppressive mode of action for growth-differentiation factor 11 (GDF11) and an unusual mechanism of its inactivation in TNBC. GDF11 promotes an epithelial, anti-invasive phenotype in 3D triple-negative cultures and intraductal xenografts by sustaining expression of E-cadherin and inhibitor of differentiation 2 (ID2). Surprisingly, clinical TNBCs retain the GDF11 locus and expression of the protein itself. GDF11 bioactivity is instead lost because of deficiencies in its convertase, proprotein convertase subtilisin/kexin type 5 (PCSK5), causing inactive GDF11 precursor to accumulate intracellularly. PCSK5 reconstitution mobilizes the latent TNBC reservoir of GDF11 in vitro and suppresses triple-negative mammary cancer metastasis to the lung of syngeneic hosts. Intracellular GDF11 retention adds to the concept of tumor-suppressor inactivation and reveals a cell-biological vulnerability for TNBCs lacking therapeutically actionable mutations.

Hypoxic Induction of Vasorin Regulates Notch1 Turnover to Maintain Glioma Stem-like Cells

Tumor hypoxia is associated with poor patient survival and is a characteristic of glioblastoma. Notch signaling is implicated in maintaining glioma stem-like cells (GSCs) within the hypoxic niche, although the molecular mechanisms linking hypoxia to Notch activation have not been clearly delineated. Here we show that Vasorin is a critical link between hypoxia and Notch signaling in GSCs. Vasorin is preferentially induced in GSCs by a HIF1α/STAT3 co-activator complex and stabilizes Notch1 protein at the cell membrane. This interaction prevents Numb from binding Notch1, rescuing it from Numb-mediated lysosomal degradation. Thus, Vasorin acts as a switch to augment Notch signaling under hypoxic conditions. Vasorin promotes tumor growth and reduces survival in mouse models of glioblastoma, and its expression correlates with increased aggression of human gliomas. These findings provide mechanistic insights into how hypoxia promotes Notch signaling in glioma and identify Vasorin as a potential therapeutic target.

Recent Advances in ADAM17 Research: A Promising Target for Cancer and Inflammation

Since its discovery, ADAM17, also known as TNFα converting enzyme or TACE, is now known to process over 80 different substrates. Many of these substrates are mediators of cancer and inflammation. The field of ADAM metalloproteinases is at a crossroad with many of the new potential therapeutic agents for ADAM17 advancing into the clinic. Researchers have now developed potential drugs for ADAM17 that are selective and do not have the side effects which were seen in earlier chemical entities that targeted this enzyme. ADAM17 inhibitors have broad therapeutic potential, with properties ranging from tumor immunosurveillance and overcoming drug and radiation resistance in cancer, as treatments for cardiac hypertrophy and inflammatory conditions such as inflammatory bowel disease and rheumatoid arthritis. This review focuses on substrates and inhibitors identified more recently for ADAM17 and their role in cancer and inflammation.

SheddomeDB: the ectodomain shedding database for membrane-bound shed markers

BACKGROUND

A number of membrane-anchored proteins are known to be released from cell surface via ectodomain shedding. The cleavage and release of membrane proteins has been shown to modulate various cellular processes and disease pathologies. Numerous studies revealed that cell membrane molecules of diverse functional groups are subjected to proteolytic cleavage, and the released soluble form of proteins may modulate various signaling processes. Therefore, in addition to the secreted protein markers that undergo secretion through the secretory pathway, the shed membrane proteins may comprise an additional resource of noninvasive and accessible biomarkers. In this context, identifying the membrane-bound proteins that will be shed has become important in the discovery of clinically noninvasive biomarkers. Nevertheless, a data repository for biological and clinical researchers to review the shedding information, which is experimentally validated, for membrane-bound protein shed markers is still lacking.

RESULTS

In this study, the database SheddomeDB was developed to integrate publicly available data of the shed membrane proteins. A comprehensive literature survey was performed to collect the membrane proteins that were verified to be cleaved or released in the supernatant by immunological-based validation experiments. From 436 studies on shedding, 401 validated shed membrane proteins were included, among which 199 shed membrane proteins have not been annotated or validated yet by existing cleavage databases. SheddomeDB attempted to provide a comprehensive shedding report, including the regulation of shedding machinery and the related function or diseases involved in the shedding events. In addition, our published tool ShedP was embedded into SheddomeDB to support researchers for predicting the shedding event on unknown or unrecorded membrane proteins.

CONCLUSIONS

To the best of our knowledge, SheddomeDB is the first database for the identification of experimentally validated shed membrane proteins and currently may provide the most number of membrane proteins for reviewing the shedding information. The database included membrane-bound shed markers associated with numerous cellular processes and diseases, and some of these markers are potential novel markers because they are not annotated or validated yet in other databases. SheddomeDB may provide a useful resource for discovering membrane-bound shed markers. The interactive web of SheddomeDB is publicly available at http://bal.ym.edu.tw/SheddomeDB/ .

Plasma proteome and metabolome characterization of an experimental human thyrotoxicosis model

BACKGROUND

Determinations of thyrotropin (TSH) and free thyroxine (FT4) represent the gold standard in evaluation of thyroid function. To screen for novel peripheral biomarkers of thyroid function and to characterize FT4-associated physiological signatures in human plasma we used an untargeted OMICS approach in a thyrotoxicosis model.

METHODS

A sample of 16 healthy young men were treated with levothyroxine for 8 weeks and plasma was sampled before the intake was started as well as at two points during treatment and after its completion, respectively. Mass spectrometry-derived metabolite and protein levels were related to FT4 serum concentrations using mixed-effect linear regression models in a robust setting. To compile a molecular signature discriminating between thyrotoxicosis and euthyroidism, a random forest was trained and validated in a two-stage cross-validation procedure.

RESULTS

Despite the absence of obvious clinical symptoms, mass spectrometry analyses detected 65 metabolites and 63 proteins exhibiting significant associations with serum FT4. A subset of 15 molecules allowed a robust and good prediction of thyroid hormone function (AUC = 0.86) without prior information on TSH or FT4. Main FT4-associated signatures indicated increased resting energy expenditure, augmented defense against systemic oxidative stress, decreased lipoprotein particle levels, and increased levels of complement system proteins and coagulation factors. Further association findings question the reliability of kidney function assessment under hyperthyroid conditions and suggest a link between hyperthyroidism and cardiovascular diseases via increased dimethylarginine levels.

CONCLUSION

Our results emphasize the power of untargeted OMICs approaches to detect novel pathways of thyroid hormone action. Furthermore, beyond TSH and FT4, we demonstrated the potential of such analyses to identify new molecular signatures for diagnosis and treatment of thyroid disorders. This study was registered at the German Clinical Trials Register (DRKS) [DRKS00011275] on the 16th of November 2016.

Genomic analysis reveals selection in Chinese native black pig

Identification of genomic signatures that help reveal mechanisms underlying desirable traits in domesticated pigs is of significant biological, agricultural and medical importance. To identify the genomic footprints left by selection during domestication of the Enshi black pig, a typical native and meat-lard breed in China, we generated about 72-fold coverage of the pig genome using pools of genomic DNA representing three different populations of Enshi black pigs from three different locations. Combining this data with the available whole genomes of 13 Chinese wild boars, we identified 417 protein-coding genes embedded in the selected regions of Enshi black pigs. These genes are mainly involved in developmental and metabolic processes, response to stimulus, and other biological processes. Signatures of selection were detected in genes involved in body size and immunity (RPS10 and VASN), lipid metabolism (GSK3), male fertility (INSL6) and developmental processes (TBX19). These findings provide a window into the potential genetic mechanism underlying development of desirable phenotypes in Enshi black pigs during domestication and subsequent artificial selection. Thus, our results illustrate how domestication has shaped patterns of genetic variation in Enshi black pigs and provide valuable genetic resources that enable effective use of pigs in agricultural production.