Matrix metalloproteinase 9 induces endothelial-mesenchymal transition via Notch activation in human kidney glomerular endothelial cells

Cornus officinalis var. koreana Kitam extracts alleviate cadmium-induced renal fibrosis by targeting matrix metallopeptidase 9

ETHNOPHARMACOLOGICAL RELEVANCE

Cornus officinalis var. koreana Kitam (Cornus officinalis) is a commonly used Chinese herbal medicine and has a good clinical efficacy in kidney and liver diseases. Recent years, a number of studies reported the significant effects of Cornus officinalis on renal fibrosis. However, it is still unclear about the underlying specific mechanism, the bioactive ingredients, and the target gene regulatory network.

AIM OF THE STUDY

We investigated the impact of Cornus officinalis extract on cadmium-induced renal fibrosis, screened the bioactive ingredients of Cornus officinalis using a pharmacological sub-network analysis, and explored the regulatory effects of Cornus officinalis extracts on target gene matrix metallopeptidase 9 (MMP9).

METHODS

Male C57BL/6N mice were treated with single or combinatorial agents such as saline, cadmium chloride, Cornus officinalis, Isoginkgetin and FSL-1. Isoginkgetin is a compound with anti-MMP9 activity. FSL-1 can induce MMP9 expression. Masson staining and Western blot and immunohistochemistry analyses were used for assessing renal fibrosis. In addition, wound healing model was established using BUMPT (Boston university mouse proximal tubular) cells to investigate how Cornus officinalis affected cadmium-induced cell migration. The main Cornus officinalis bioactive compounds were identified by UHPLC-MS (Ultra-high-performance liquid chromatography - mass spectrometry). The MMP9 target for Cornus officinalis active ingredients were confirmed through a pharmacological sub-network analysis.

RESULTS

Aqueous extracts of Cornus officinalis protected from renal dysfunction and kidney fibrosis induced by cadmium chloride in mice. In vitro experiments validated that Cornus officinalis extracts inhibited cell migration ability especially in cadmium chloride condition. The sub-network analysis and chemical components profiling technique revealed the active compounds of Cornus officinalis. Cellular thermal shift assay verified the binding abilities of three active components Daidzein, N-Acetyl-L-tyrosine or Swertisin with matrix metalloproteinase-9. Gelatin zymography assay revealed that the activity of MMP9 was inhibited by the three active components. We further confirmed that MMP9 was involved in the process of Cornus officinalis extracts reducing renal fibrosis. Cornus officinalis attenuated the cadmium-induced renal fibrosis was correlated with decreased expression of MMP9, collagen I, α-SMA (alpha-smooth muscle actin) and vimentin.

CONCLUSIONS

This study demonstrated that Cornus officinalis extracts could alleviate the cadmium chloride-induced renal fibrosis by targeting MMP9, and might provide new insights into the mechanism of treating renal fibrosis by Cornus officinalis.

Linking inflammation and angiogenesis with fibrogenesis: Expression of FXIIIA, MMP-9, and VEGF in oral submucous fibrosis

OBJECTIVES

Interplay of Factor XIIIa (FXIIIa), a transglutaminase, responsible for cross-linking of matrix proteins, Matrix Metalloproteinase-9 (MMP-9), a gelatinase, and Vascular Endothelial Growth Factor (VEGF), an angiogenic inducer, were studied in relation to fibrogenesis and disease progression in oral submucous fibrosis (OSMF).

MATERIAL AND METHODS

Immunohistochemical expression of markers was studied in 60 formalin-fixed paraffin-embedded tissue blocks of OSMF and 20 normal oral mucosal tissues. FXIIIa was studied quantitatively while MMP-9 and VEGF were assessed semi-quantitatively. Expression was compared with histopathological grades of OSMF.

RESULTS

FXIIIa expression significantly increased in OSMF (p-value 0.000). However, expression decreased and cells became quiescent with increasing grades (p-value 0.000). MMP-9 (p-value epithelium 0.011, p-value connective tissue 0.000) and VEGF expression (p-value epithelium 0.000, connective tissue 0.000) increased in OSMF. A negative correlation between FXIIIa and MMP-9 (-0.653) in early grade (p-value of 0.021) and a positive correlation between FXIIIa and VEGF (0.595) (p-value of 0.032) was found in the moderate grade OSMF. Regression analysis showed a significant association (p<0.01) of FXIIIa in OSMF and with increasing grades of OSMF.

CONCLUSION

FXIIIa may play a crucial role in initiation of fibrosis in OSMF. MMP-9 may have a diverse role to play in OSMF as a regulator of fibrosis. VEGF may show an angio-fibrotic switch and contribute to fibrosis in OSMF. These cytokines may show altered function and can contribute to fibrosis and chronicity of disease due to changes in the microenvironment. Tissue stiffness in OSMF itself creates an environment that enhances the chronicity of the disease.

Keratin 15 protects against cigarette smoke-induced epithelial mesenchymal transformation by MMP-9

BACKGROUND

Chronic obstructive pulmonary disease (COPD), a chronic inflammatory lung disease, is a leading cause of morbidity and mortality worldwide. Prolonged cigarette smoking (CS) that causes irreversible airway remodeling and significantly reduces lung function is a major risk factor for COPD. Keratin15+ (Krt15+) cells with the potential of self-renewal and differentiation properties have been implicated in the maintenance, proliferation, and differentiation of airway basal cells; however, the role of Krt15 in COPD is not clear.

METHODS

Krt15 knockout (Krt15-/-) and wild-type (WT) mice of C57BL/6 background were exposed to CS for six months to establish COPD models. Krt15-CrePGR;Rosa26-LSL-tdTomato mice were used to trace the fate of the Krt15+ cells. Hematoxylin and eosin (H&E) and Masson stainings were performed to assess histopathology and fibrosis, respectively. Furthermore, lentivirus-delivered short hairpin RNA (shRNA) was used to knock down KRT15 in human bronchial epithelial (HBE) cells stimulated with cigarette smoke extract (CSE). The protein expression was assessed using western blot, immunohistochemistry, and enzyme-linked immunosorbent assay.

RESULTS

Krt15-/- CS mice developed severe inflammatory cell infiltration, airway remodeling, and emphysema. Moreover, Krt15 knockout aggravated CS-induced secretion of matrix metalloproteinase-9 (MMP-9) and epithelial-mesenchymal transformation (EMT), which was reversed by SB-3CT, an MMP-9 inhibitor. Consistent with this finding, KRT15 knockdown promoted MMP-9 expression and EMT progression in vitro. Furthermore, Krt15+ cells gradually increased in the bronchial epithelial cells and were transformed into alveolar type II (AT2) cells.

CONCLUSION

Krt15 regulates the EMT process by promoting MMP-9 expression and protects the lung tissue from CS-induced injury, inflammatory infiltration, and apoptosis. Furthermore, Krt15+ cells transformed into AT2 cells to protect alveoli. These results suggest Krt15 as a potential therapeutic target for COPD.

Inhibition of PRMT1 alleviates sepsis-induced acute kidney injury in mice by blocking the TGF-β1 and IL-6 trans-signaling pathways

Sepsis-induced acute kidney injury (SI-AKI) causes renal dysfunction and has a high mortality rate. Protein arginine methyltransferase-1 (PRMT1) is a key regulator of renal insufficiency. In the present study, we explored the potential involvement of PRMT1 in SI-AKI. A murine model of SI-AKI was induced by cecal ligation and perforation. The expression and localization of PRMT1 and molecules involved in the transforming growth factor (TGF)-β1/Smad3 and interleukin (IL)-6/signal transducer and activator of transcription 3 (STAT3) signaling pathways were detected in mouse kidney tissues by western blot analysis, immunofluorescence, and immunohistochemistry. The association of PRMT1 with downstream molecules of the TGF-β1/Smad3 and IL-6/STAT3 signaling pathways was further verified in vitro in mouse renal tubular epithelial cells. Cecal ligation and perforation caused epithelial-mesenchymal transition, apoptosis, and inflammation in renal tissues, and this was alleviated by inhibition of PRMT1. Inhibition of PRMT1 in SI-AKI mice decreased the expression of TGF-β1 and phosphorylation of Smad3 in the renal cortex, and downregulated the expression of soluble IL-6R and phosphorylation of STAT3 in the medulla. Knockdown of PRMT1 in mouse renal tubular epithelial cells restricted the expression of Cox-2, E-cadherin, Pro-caspase3, and phosphorylated Smad3 (involved in the TGF-β1-mediated signaling pathway), and also blocked IL-6/soluble IL-6R, inducing the expression of Cox-2 and phosphorylated-STAT3. In conclusion, our findings suggest that inhibition of PRMT1 mitigates SI-AKI by inactivating the TGF-β1/Smad3 pathway in the cortex and the IL-6/STAT3 pathway in the medulla. Our findings may aid in the identification of potential therapeutic target molecules for SI-AKI.

Plasma-derived small extracellular vesicles unleash the angiogenic potential in head and neck cancer patients

BACKGROUND

In Head and neck cancer (HNC) angiogenesis is essential for tumor progression and metastasis. Small extracellular vesicles (sEVs) from HNC cell lines alter endothelial cell (EC) functions towards a pro-angiogenic phenotype. However, the role of plasma sEVs retrieved from HNC patients in this process is not clear so far.

METHODS

Plasma sEVs were isolated on size exclusion chromatography columns from 32 HNC patients (early-stage UICC I/II: 8, advanced-stage UICC III/IV: 24), 12 patients with no evident disease after therapy (NED) and 16 healthy donors (HD). Briefly, sEVs were characterized by transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), BCA protein assays and Western blots. Levels of angiogenesis-associated proteins were determined using antibody arrays. The interaction of fluorescently-labeled sEVs with human umbilical vein ECs was visualized by confocal microscopy. The functional effect of sEVs on tubulogenesis, migration, proliferation and apoptosis of ECs was assessed.

RESULTS

The internalization of sEVs by ECs was visualized using confocal microscopy. Based on antibody arrays, all plasma sEVs were enriched in anti-angiogenic proteins. HNC sEVs contained more pro-angiogenic MMP-9 and anti-angiogenic proteins (Serpin F1) than HD sEVs. Interestingly, a strong inhibition of EC function was observed for sEVs from early-stage HNC, NED and HD. In contrast, sEVs from advanced-stage HNC showed a significantly increased tubulogenesis, migration and proliferation and induced less apoptosis in ECs than sEVs from HD.

CONCLUSIONS

In general, plasma sEVs carry a predominantly anti-angiogenic protein cargo and suppress the angiogenic properties of ECs, while sEVs from (advanced-stage) HNC patients induce angiogenesis compared to HD sEVs. Thus, tumor-derived sEVs within the plasma of HNC patients might shift the angiogenic switch towards angiogenesis.

Microenvironment commits breast tumor ECs to dedifferentiation by micro-RNA-200-b-3p regulation and extracellular matrix remodeling

Introduction: Hypoxia shapes the tumor microenvironment, modulates distinct cell population activities, and activates pathological angiogenesis in cancer, where endothelial cells (ECs) are the most important players. This study aimed to evidence the influences of the tumor microenvironment on the global gene expression pattern characteristic for ECs and the distinct responses displayed by tumor-derived ECs in comparison to the healthy endothelium during endothelial to mesenchymal transition (EndMT) and its regulation by miR-200-b-3p. Methodology: Immortalized lines of ECs from the same patient with breast cancer, healthy breast tissue (HBH.MEC), and primary tumor (HBCa.MEC) were used. The experiments were performed in normoxia and hypoxia for 48 h. By using the wound healing test, we investigated the migration abilities of ECs. Global gene expression analysis with NGS was carried out to detect new pathways altered in pathological ECs and find the most changed miRNAs. The validation of NGS data from RNA and miRNA was estimated by qPCRs. Mimic miR-200b-3p was used in HBH.MEC, and the targets VEGF, Bcl2, ROCK2, and SP1 were checked. Results: Hypoxia influences EC migration properties in wound healing assays. In hypoxia, healthy ECs migrate slower than they do in normoxia, as opposed to HBCa.MEC, where no decreased migration ability is induced by hypoxia due to EndMT features. NGS data identified this process to be altered in cancer ECs through extracellular matrix (ECM) organization. The deregulated genes, validated by qPCR, included SPP1, ITGB6, COL4A4, ADAMST2, LAMA1, GAS6, PECAM1, ELN, FBLN2, COL6A3, and COL9A3. NGS also identified collagens, laminins, fibronectins, and integrins, as being deregulated in tumor-derived ECs. Moreover, the analysis of the 10 most intensively modified miRNAs, when breast tumor-derived ECs were compared to healthy ECs, shed light on miR-200b-3p, which is strongly upregulated in HBCa.MECs when compared to HBH.MECs. Discussion and conclusion: The pathological ECs differed significantly, both phenotypically and functionally, from the normal corresponding tissue, thus influencing their microenvironment cross-talk. The gene expression profile confirms the EndMT phenotype of tumor-derived ECs and migratory properties acquisition. Moreover, it indicates the role of miR-200b-3p, that is, regulating EndMT in pathological ECs and silencing several angiogenic growth factors and their receptors by directly targeting their mRNA transcripts.

Cancer-Associated Fibroblasts in Hepatocellular Carcinoma and Cholangiocarcinoma

Primary liver cancer (PLC) includes hepatocellular carcinoma and intrahepatic cholangiocarcinoma and is the sixth most common cancer worldwide with poor prognosis. PLC is characterized by an abundant stromal reaction in which cancer-associated fibroblasts (CAFs) are one of the major stromal components. Solid evidence has demonstrated the crucial role of CAFs in tumor progression, and CAF abundance is often correlated with poor clinical outcomes. Although CAFs are regarded as an attractive and promising target for PLC treatment, a poor understanding of CAF origins and heterogeneity and a lack of specific CAF markers are the major hurdles to efficient CAF-specific therapy. In this review, we examine recent advances in the understanding of CAF diversity in the context of biomarkers, subtypes, and functions in PLC. The regulatory roles of CAFs in extracellular matrix remodeling, metastasis, cancer stemness, and therapeutic resistance are summarized. With an increasing link between CAF abundance and reduced antitumor immune responses, we provide updated knowledge on the crosstalk between CAFs and immune cells within the tumor microenvironment, which leads to immune resistance. In addition, we present current CAF-targeted therapies and describe some future perspectives. A better understanding of CAF biology will shed light on a novel therapeutic strategy against PLC.

Single cell RNA sequencing analysis of mouse cochlear supporting cell transcriptomes with activated ERBB2 receptor indicates a cell-specific response that promotes CD44 activation

Hearing loss caused by the death of cochlear hair cells (HCs) might be restored through regeneration from supporting cells (SCs) via dedifferentiation and proliferation, as observed in birds. In a previous report, ERBB2 activation in a subset of cochlear SCs promoted widespread down-regulation of SOX2 in neighboring cells, proliferation, and the differentiation of HC-like cells. Here we analyze single cell transcriptomes from neonatal mouse cochlear SCs with activated ERBB2, with the goal of identifying potential secreted effectors. ERBB2 induction in vivo generated a new population of cells with de novo expression of a gene network. Called small integrin-binding ligand n-linked glycoproteins (SIBLINGs), these ligands and their regulators can alter NOTCH signaling and promote cell survival, proliferation, and differentiation in other systems. We validated mRNA expression of network members, and then extended our analysis to older stages. ERBB2 signaling in young adult SCs also promoted protein expression of gene network members. Furthermore, we found proliferating cochlear cell aggregates in the organ of Corti. Our results suggest that ectopic activation of ERBB2 signaling in cochlear SCs can alter the microenvironment, promoting proliferation and cell rearrangements. Together these results suggest a novel mechanism for inducing stem cell-like activity in the adult mammalian cochlea.

Cellular phenotypic transitions in diabetic nephropathy: An update

Diabetic nephropathy (DN) is a major cause of morbidity and mortality in diabetes and is the most common cause of end stage renal disease (ESRD). Renal fibrosis is the final pathological change in DN. It is widely believed that cellular phenotypic switching is the cause of renal fibrosis in diabetic nephropathy. Several types of kidney cells undergo activation and differentiation and become reprogrammed to express markers of mesenchymal cells or podocyte-like cells. However, the development of targeted therapy for DN has not yet been identified. Here, we discussed the pathophysiologic changes of DN and delineated the possible origins that contribute to myofibroblasts and podocytes through phenotypic transitions. We also highlight the molecular signaling pathways involved in the phenotypic transition, which would provide valuable information for the activation of phenotypic switching and designing effective therapies for DN.

The circRERE/miR-144-3p/TLR2/MMP9 signaling axis in COPD pulmonary monocytes promotes the EMT of pulmonary epithelial cells

Chronic obstructive pulmonary disease (COPD) is a serious threat to human health, but an effective targeted therapy for COPD is still lacking at present. During the progression of COPD, the epithelial mesenchymal transition (EMT) ensures the remodeling of pulmonary epithelial cells, and it could not be precisely targeted due to its complex and elusive mechanism. In this study, we determined that the TLR2/MMP9 axis is upregulated in the pulmonary monocytes in cigarette smoke (CS)-induced COPD mice. Using a co-culture system, we identified that the TLR2/MMP9 axis in pulmonary monocytes promotes the EMT of pulmonary epithelial cells. Further, our results confirmed that miR-144-3p inhibits TLR2 expression in monocytes by directly binding to the 3'UTR of TLR2. Finally, we proved that circRERE works as a sponge to antagonize miR-144-3p and promote TLR2 expression in monocytes. Thus, our results conclude that the circRERE/miR-144-3p/TLR2/MMP9 axis in COPD pulmonary monocytes is critical for CS-induced COPD and circRERE may serve as a potential target for COPD.

Role of MMP3 and fibroblast-MMP14 in skin homeostasis and repair

Early lethality of mice with complete deletion of the matrix metalloproteinase MMP14 emphasized the proteases' pleiotropic functions. MMP14 deletion in adult dermal fibroblasts (MMP14^Sf-/-) caused collagen type I accumulation and upregulation of MMP3 expression. To identify the compensatory role of MMP3, mice were generated with MMP3 deletion in addition to MMP14 loss in fibroblasts. These double deficient mice displayed a fibrotic phenotype in skin and tendons as detected in MMP14^Sf-/- mice, but no additional obvious defects were detected. However, challenging the mice with full thickness excision wounds resulted in delayed closure of early wounds in the double deficient mice compared to wildtype and MMP14 single knockout controls. Over time wounds closed and epidermal integrity was restored. Interestingly, on day seven, post-wounding myofibroblast density was lower in the wounds of all knockout than in controls, they were higher on day 14. The delayed resolution of myofibroblasts from the granulation tissue is paralleled by reduced apoptosis of these cells, although proliferation of myofibroblasts is induced in the double deficient mice. Further analysis showed comparable TGFβ1 and TGFβR1 expression among all genotypes. In addition, in vitro, fibroblasts lacking MMP3 and MMP14 retained their ability to differentiate into myofibroblasts in response to TGFβ1 treatment and mechanical stress. However, in vivo, p-Smad2 was reduced in myofibroblasts at day 5 post-wounding, in double, but most significant in single knockout, indicating their involvement in TGFβ1 activation. Thus, although MMP3 does not compensate for the lack of fibroblast-MMP14 in tissue homeostasis, simultaneous deletion of both proteases in fibroblasts delays wound closure during skin repair. Notably, single and double deficiency of these proteases modulates myofibroblast formation and resolution in wounds.

TIMP3 involvement and potentiality in the diagnosis, prognosis and treatment of diabetic nephropathy

Diabetic kidney disease, one of the most severe complications associated with diabetes, is characterized by albuminuria, glomerulosclerosis and progressive loss of renal function. Loss of TIMP3, an Extracellular matrix-bound protein, is a hallmark of diabetic nephropathy in human and mouse models, suggesting its pivotal role in renal diseases associated to diabetes. There is currently no specific therapy for diabetic nephropathy, and the ability to restore high TIMP3 activity specifically in the kidney may represent a potential therapeutic strategy for the amelioration of renal injury under conditions in which its reduction is directly related to the disease. Increasing evidence shows that diabetic nephropathy is also regulated by epigenetic mechanisms, including noncoding RNA. This review recapitulates the pathological, diagnostic and therapeutic potential roles of TIMP3 and the noncoding RNA (microRNA, long noncoding RNA) related to its expression, in the progression of diabetic nephropathy.

The Role of Macrophages in Kidney Fibrosis

The phenotypic heterogeneity and functional diversity of macrophages confer on them complexed roles in the development and progression of kidney diseases. After kidney injury, bone marrow-derived monocytes are rapidly recruited to the glomerulus and tubulointerstitium. They are activated and differentiated on site into pro-inflammatory M1 macrophages, which initiate Th1-type adaptive immune responses and damage normal tissues. In contrast, anti-inflammatory M2 macrophages induce Th2-type immune responses, secrete large amounts of TGF-β and anti-inflammatory cytokines, transform into αSMA+ myofibroblasts in injured kidney, inhibit immune responses, and promote wound healing and tissue fibrosis. Previous studies on the role of macrophages in kidney fibrosis were mainly focused on inflammation-associated injury and injury repair. Apart from macrophage-secreted profibrotic cytokines, such as TGF-β, evidence for a direct contribution of macrophages to kidney fibrosis is lacking. However, under inflammatory conditions, Wnt ligands are derived mainly from macrophages and Wnt signaling is central in the network of multiple profibrotic pathways. Largely underinvestigated are the direct contribution of macrophages to profibrotic signaling pathways, macrophage phenotypic heterogeneity and functional diversity in relation to kidney fibrosis, and on their cross-talk with other cells in profibrotic signaling networks that cause fibrosis. Here we aim to provide an overview on the roles of macrophage phenotypic and functional diversity in their contribution to pro-fibrotic signaling pathways, and on the therapeutic potential of targeting macrophages for the treatment of kidney fibrosis.

IFN-I Mediates Lupus Nephritis From the Beginning to Renal Fibrosis

Lupus nephritis (LN) is a common complication of systemic lupus erythematosus (SLE) and a major risk factor for morbidity and mortality. The abundant cell-free nucleic (DNA/RNA) in SLE patients, especially dsDNA, is a key substance in the pathogenesis of SLE and LN. The deposition of DNA/RNA-immune complexes (DNA/RNA-ICs) in the glomerulus causes a series of inflammatory reactions that lead to resident renal cell disturbance and eventually renal fibrosis. Cell-free DNA/RNA is the most effective inducer of type I interferons (IFN-I). Resident renal cells (rather than infiltrating immune cells) are the main source of IFN-I in the kidney. IFN-I in turn damages resident renal cells. Not only are resident renal cells victims, but also participants in this immunity war. However, the mechanism for generation of IFN-I in resident renal cells and the pathological mechanism of IFN-I promoting renal fibrosis have not been fully elucidated. This paper reviews the latest epidemiology of LN and its development process, discusses the mechanism for generation of IFN-I in resident renal cells and the role of IFN-I in the pathogenesis of LN, and may open a new perspective for the treatment of LN.

Matrix metalloproteinases and their inhibitors in Fuchs endothelial corneal dystrophy

Fuchs endothelial corneal dystrophy (FECD) is characterized by a progressive loss of corneal endothelial cells (CECs) and an abnormal accumulation of extracellular matrix in Descemet's membrane leading to increased thickness and formation of excrescences called guttae. Extracellular matrix homeostasis is modulated by an equilibrium between matrix metalloproteinases (MMPs) and their endogenous tissue inhibitors (TIMPs). This study aimed to investigate MMPs and TIMPs profile in FECD, taking into account cell morphology. Populations of FECD and healthy CECs were cultured and their conditioned media collected for analysis. The presence of proteases in the conditioned media was studied using a semi-quantitative proteome profiler array, and MMPs levels were assessed using quantitative assays (ELISA and quantitative antibody array). MMP activity was determined by zymography and fluorometry. The expression pattern of the membrane type 1-MMP (MT1-MMP, also known as MMP-14) was examined by immunofluorescence on ex vivo FECD and healthy explants of CECs attached to Descemet's membrane. Finally, MMPs and TIMPs protein expression was compared to gene expression obtained from previously collected data. FECD and healthy CEC populations generated cultures of endothelial, intermediate, and fibroblastic-like morphology. Various MMPs (MMP-1, -2, -3, -7, -8, -9, -10, and -12) and TIMPs (TIMP-1 to -4) were detected in both FECD and healthy CECs culture supernatants. Quantitative assays revealed a decrease in MMP-2 and MMP-10 among FECD samples. Both these MMPs can degrade the main extracellular matrix components forming guttae (fibronectin, laminin, collagen IV). Moreover, MMPs/TIMPs ratio was also decreased among FECD cell populations. Activity assays showed greater MMPs/Pro-MMPs proportions for MMP-2 and MMP-10 in FECD cell populations, although overall activities were similar. Moreover, the analysis according to cell morphology revealed among healthy CECs, both increased (MMP-3 and -13) and decreased (MMP-1, -9, -10, and -12) MMPs proteins along with increased MMPs activity (MMP-2, -3, -9, and -10) in the fibroblastic-like subgroup when compared to the endothelial subgroup. However, FECD CECs did not show similar behaviors between the different morphology subgroups. Immunostaining of MT1-MMP on ex vivo FECD and healthy explants revealed a redistribution of MT1-MMP around guttae in FECD explants. At the transcriptional level, no statistically significant differences were detected, but cultured FECD cells had a 12.2-fold increase in MMP1 and a 4.7-fold increase in TIMP3. These results collectively indicate different, and perhaps pathological, MMPs and TIMPs profile in FECD CECs compared to healthy CECs. This is an important finding suggesting the implication of MMPs and TIMPs in FECD pathophysiology.

Restoration of renal TIMP3 levels via genetics and pharmacological approach prevents experimental diabetic nephropathy

BACKGROUND

Diabetic nephropathy (DN), one of the major complications of diabetes, is characterized by albuminuria, glomerulosclerosis, and progressive loss of renal function. Loss of TIMP3, an Extracellular Matrix bound protein affecting both inflammation and fibrosis, is a hallmark of DN in human subjects and mouse models.

METHODS

This study was designed to provide evidences that the modulation of the system involving TIMP3 and its target A Disintegrin And Metalloproteinase 17 (ADAM17), may rescue kidney pathology in diabetic mice. Mice with cell-targeted overexpression of TIMP3 in myeloid cells (MacT3), podocyte-specific ADAM17 knockout mice (∆PodA17), and DBA/2J mice, were rendered diabetic at 8 weeks of age with a low-dose streptozotocin protocol. DBA/2J mice were administered new peptides based on the human TIMP3 N-terminal domain, specifically conjugated with G3C12, a carrier peptide highly selective and efficient for transport to the kidney. Twelve weeks after Streptozotocin injections, 24-hour albuminuria was determined by ELISA, kidney morphometry was analyzed by periodic acid-shift staining, and Real Time-PCR and western blot analysis were performed on mRNA and protein extracted from kidney cortex.

RESULTS

Our results showed that both genetic modifications and peptides treatment positively affect renal function and structure in diabetic mice, as indicated by a significant and consistent decline in albuminuria along with reduction in glomerular lesions, as indicated by reduced mesangial expansion and glomerular hypertrophy, decreased deposition of extracellular matrix in the mesangium, diminished protein expression of the NADPH oxidases 4 (NOX4), and the improvement of podocyte structural markers such as WT1, nephrin, and podocin. Moreover, the positive effects were exerted through a mechanism independent from glycemic control.

CONCLUSIONS

In diabetic mice the targeting of TIMP3 system improved kidney structure and function, representing a valid approach to develop new avenues to treat this severe complication of diabetes.

Role of MMP-9 in epithelial-mesenchymal transition of thyroid cancer

Background

The purpose of this study is to explore the role and mechanism of MMP-9 in the EMT process of thyroid cancer (TC), so as to provide a basis for clinical exploration of invasion and metastasis process of TC, looking for biological markers of tumor metastasis and molecular intervention therapy.

Methods

Western blot and RT-PCR were employed to detect the expression of MMP-9 in human normal thyroid cell line HT-ori3 and human TC cell lines IHH-4 (PTC), FTC-133, and 8505C. Expression levels of EMT-related markers: epithelial cell marker E-cadherin and stromal cell marker Vimentin in TGF-1-induced TC cell lines were detected by Western blot and RT-PCR, respectively. The effects of MMP-9 downregulation on cell invasion and metastasis were investigated by wound-healing assay and cell invasion experiment.

Results

The protein and mRNA expression levels of MMP-9 in TC cell lines were increased compared with the human normal thyroid cell line HT-ori3. When TGF-β1 was added, the expression of EMT and Vimentin increased while the expression of E-cadherin decreased. Compared with the control group, the TC cells stably transfected with MMP-9 shRNA showed inhibited EMT, decreased Vimentin expression, and increased E-cadherin expression. The induction of TGF-β1 did not promote the occurrence of EMT in TC cells which were stably transformed with MMP-9 shRNA. The addition of TGF-β1 to TC cells increased the ability of the cells to migrate and invade. Compared with the control group, the migration and invasion ability of TC cells stably transfected with MMP-9 shRNA was significantly reduced, and the induction of TGF-β1 could not restore the migration and invasion ability of cells without MMP-9.

Conclusions

In conclusion, we found that MMP-9 can be used as a biomarker for TC, which can promote the EMT process of TGF-β1 induced TC, and thus affecting the cell migration and invasion ability.

Exploring a peptidomimetic approach of N-cadherin in modulating fibroblast growth factor receptor signaling for corneal endothelial regeneration

Endothelial rejection and a critical shortage of corneal transplants present an unmet medical need in corneal regeneration research area. Although basic fibroblast growth factor (bFGF) is a potent mitogenic factor for corneal ex vivo expansion, it is also a morphogen eliciting unfavorable endothelial-mesenchymal transition (EnMT) of corneal endothelial cells. A pharmacological reagent that retains the beneficial proliferative effect while lacking the EnMT effect of bFGF would be of great potential in corneal regeneration. In present study, we demonstrated that bFGF not only activated the canonical fibroblast growth factor receptor 1 (FGFR1) tyrosine kinase pathway, but also further upregulated matrix metalloproteinase activity to cleave N-cadherin into N-terminus and C-terminus fragments, which activated the classical FGFR1 tyrosine kinase pathway and a cryptic β-catenin pathway to affect corneal proliferation and EnMT, respectively. We generated the synthetic peptides resembling a critical motif in the ectodomain of N-cadherin and found these peptides enhanced downstream proliferative signaling of FGFR1 but without seemingly EnMT effect. The potential of these peptides can be demonstrated on both ex vivo cell culture and in vivo rat cryo-injury model. Our study indicated this peptidomimetic approach of N-cadherin can stimulate corneal regeneration and offer a promising therapeutic option to treat corneal endothelial dysfunction.

Shp2 positively regulates cigarette smoke-induced epithelial mesenchymal transition by mediating MMP-9 production

Cigarette smoke (CS) is a major risk factor for the development of lung cancer and chronic obstructive pulmonary disease (COPD). Epithelial-mesenchymal transition (EMT) commonly coexists in lung cancer and COPD. CS triggers many factors including matrix metalloproteinases (MMPs) production, contributing to EMT progression in the lungs. Here, how Shp2 signaling regulates the CS-induced MMP-9 production and EMT progression were investigated in mouse lungs and in pulmonary epithelial cell cultures (NCI-H292) found CS induced MMP-9 production, EMT progression (increased vimentin and α-SMA; decreased E-cadherin) and collagen deposition in lung tissues; cigarette smoke extract (CSE) induced MMP-9 production and EMT-related phenotypes in NCI-H292 cells, which were partially prevented by Shp2 KO/KD or Shp2 inhibition. The CSE exposure induced EMT phenotypes were suppressed by MMP-9 inhibition. Recombinant MMP-9 induced EMT, which was prevented by MMP-9 inhibition or Shp2 KD/inhibition. Mechanistically, CS and CSE exposure resulted in ERK1/2, JNK and Smad2/3 phosphorylation, which were suppressed by Shp2 KO/KD/inhibition. Consequentially, the CSE exposure-induced MMP-9 production and EMT progression were suppressed by ERK1/2, JNK and Smad2/3 inhibitors. Thus, CS induced MMP-9 production and EMT resulted from activation of Shp2/ERK1/2/JNK/Smad2/3 signaling pathways. Our study contributes to the underlying mechanisms of pulmonary epithelial structural changes in response to CS, which may provide novel therapeutic solutions for treating associated diseases, such as COPD and lung cancer.

Integrating the Polydopamine Nanosphere/Aptamers Nanoplatform with a DNase-I-Assisted Recycling Amplification Strategy for Simultaneous Detection of MMP-9 and MMP-2 during Renal Interstitial Fibrosis

Matrix metalloproteinase-9 (MMP-9) and matrix metalloproteinase-2 (MMP-2) play important roles in the progression of renal interstitial fibrosis (RIF). There is an increasing demand to construct a novel method for the simultaneous detection of MMP-9 and MMP-2 to monitor the progression of RIF. Herein, a strategy based on the nanoplatform composed of the polydopamine nanosphere and fluorescence-labeled aptamers is developed to simultaneously detect MMP-9 and MMP-2 with DNase-I-assisted recycling signal amplification. In the light of tracing the recovered fluorescence intensity at 520 and 610 nm upon adding MMP-9 and MMP-2, the increased fluorescence intensity is linear to the different concentrations of MMP-9 and MMP-2 with the detection limits of 9.6 and 25.6 pg/mL for MMP-9 and MMP-2, respectively. More intriguingly, the results of unilateral ureteral obstruction mice show that the concentration of MMP-9 in urine is increased with the extension of ligation time while the concentration of MMP-2 is reversed, indicating that the ratio of MMP-9 to MMP-2 could be considered as the potential urinary biomarker to evaluate the progress of RIF and the therapeutic effect of Huangkui capsule on RIF. Therefore, this study provides a paradigmatic strategy for the simultaneous detection of the dual markers of RIF, which is promising for the auxiliary clinical diagnosis and assessment of the prognosis of chronic kidney disease.

AAV-mediated TIMP-1 overexpression in aortic tissue reduces the severity of allograft vasculopathy in mice

BACKGROUND

Allograft vasculopathy (AV) is the primary limiting factor for long-term graft survival. An increased activity of matrix metalloproteinases (MMPs) contributes to neointima formation in AV and represents a potential therapeutic target. Adeno-associated virus (AAV)-mediated gene therapy comprises a potentially benign vector model for the long-term expression of MMP antagonists.

METHODS

Aortic allografts from DBA/2 mice were incubated with control buffer, AAV-enhanced green fluorescence protein (EGFP), or tissue inhibitor of metalloproteinases 1 (TIMP-1)-loaded AAV (AAV-TIMP-1) and transplanted into the infrarenal aorta of C57BL/6 mice. Cyclosporine A (10 mg/kg body weight) was administered daily. Explantation as well as histomorphometric and immunohistochemical evaluation was performed after 30 days. Matrix metalloproteinase (MMP) activity was visualized by gelatin in situ zymography.

RESULTS

Intima-to-media area ratio and neointima formation were significantly reduced in the AAV-TIMP-1 treatment group compared with those in the control group (by 40%; p < 0.001) and the AAV-EGFP group (by 38.2%; p < 0.001). TIMP-1 overexpression positively affected several pathomechanisms for the development of AV both in vitro and in vivo as compared to that in the control groups: endothelium integrity was preserved as shown by zona occludens 1 and occludin staining; MMP9 expression and activity were significantly reduced (p = 0.01); and smooth muscle cell migration was significantly reduced as smooth muscle actin positive cells predominantly remained in the aortic media in the treatment group (p = 0.001). Moreover, macrophage infiltration was markedly reduced by 49% in the AAV-TIMP-1 group (p < 0.001).

CONCLUSION

Immediate post-harvesting allograft incubation with AAV-TIMP-1 reduces neointima formation and macrophage infiltration, constituting a possible adjunct therapeutic strategy to preserve graft function after transplantation.

Overexpression of the hyperplasia suppressor gene inactivates airway fibroblasts obtained from a rat model of chronic obstructive pulmonary disease by inhibiting the Wnt signaling pathway

The present study aimed to investigate the effects of hyperplasia suppressor gene (HSG) overexpression on the activation of airway fibroblasts in a rat model of chronic obstructive pulmonary disease (COPD) and assess the underlying molecular mechanisms. The rat model of COPD was established by injection of papain and confirmed by hematoxylin and eosin staining. Airway fibroblasts were identified using immunofluorescence, and HSG expression was facilitated by an HSG vector. Cell viability, apoptosis and the levels of matrix metallopeptidase-9 (MMP-9), platelet-derived growth factor (PDGF), and transforming growth factor-β1 (TGF-β1) were measured via Cell Counting Kit-8, flow cytometry and ELISA analyses, respectively, and potential mechanisms were detected by reverse transcription-quantitative polymerase chain reaction and western blotting. Airway fibroblasts from COPD rats were isolated and identified based on vimentin expression. Compared with the control group, HSG overexpression reduced cell viability, promoted apoptosis, and reduced the protein levels of TGF-β1, MMP-9 and PDGF. Additionally, HSG overexpression reduced β-catenin and Ras homology family member A (RhoA) expression at both the mRNA and protein levels. Conversely, Wnt signaling pathway agonists lithium chloride (LiCl) and 4-ethyl-5,6-dihydro-5-methyl- (1,3)dioxolo(4,5-j)phenanthridine (HLY78), significantly reduced the effects of HSG overexpression (P<0.05 vs. HSG). Cell viability in the HSG + LiCl and HSG + HLY78 groups was increased, whereas apoptosis was reduced compared with HSG treatment alone. The protein levels of TGF-β1, MMP-9 and PDGF were also decreased in the HSG + LiCl and HSG + HLY78 groups compared with the HSG group (P<0.05). Furthermore, the expression of β-catenin and RhoA was higher in the HSG + LiCl and HSG + HLY78 groups compared with the HSG group (P<0.05). Collectively, the results indicated that HSG overexpression inactivated airway fibroblasts from COPD by inhibiting the Wnt signaling pathway.

Novel role of Snail 1 in promoting tumor neoangiogenesis

Snail1 plays an important role in epithelial to mesenchymal transition (EMT) during tumor metastasis; however, whether Snai1 potentiates the process of neoangiogenesis is completely unknown. In the present study, tube formation assay was used to evaluate neoangiogenesis in vitro The expression of Snai1 and other pro-neoangiogenic factors was measured by quantitative real time PCR. Tumor derived endothelial cells (TDECs) were stimulated with fibroblast growth factor 1 (FGF1) or VEGF and formed more tubes compared with untreated, whereas cells treated with Sulforaphane had less tube formation. Silencing SNAI1 significantly attenuated tube formation accompanied by decreased CD31, CD34, and VWF expression in TDECs compared with control. In contrast, overexpression of Snai1 led to more CD31, CD34, and VWF expression and tube formation. To determine if the observed effects of SNAI1 on tube formation was a global phenomenon, the same assay was conducted in normal mesenchymal stem cells (MSCs). SNAI1 silencing did not have any effect on tube formation in MSCs. The expression of TIMP2, ENG, and HIF1A was up-regulated 3-fold or higher after silencing SNAI1, and ID1, VEGFA, PLG, LECT1, HPSE were shown down-regulated. Taken together, our study elucidates an important role of EMT inducer Snai1 in regulating tumor neoangiogenesis, suggesting a potential therapeutic target for overcoming tumor EMT.

The extracellular matrix as a multitasking player in disease

Extracellular matrices (ECMs) are highly specialized and dynamic three-dimensional (3D) scaffolds into which cells reside in tissues. ECM is composed of a variety of fibrillar components, such as collagens, fibronectin, and elastin, and non-fibrillar molecules as proteoglycans, hyaluronan, and glycoproteins including matricellular proteins. These macromolecular components are interconnected forming complex networks that actively communicate with cells through binding to cell surface receptors and/or matrix effectors. ECMs exert diverse roles, either providing tissues with structural integrity and mechanical properties essential for tissue functions or regulating cell phenotype and functions to maintain tissue homeostasis. ECM molecular composition and structure vary among tissues, and is markedly modified during normal tissue repair as well as during the progression of various diseases. Actually, abnormal ECM remodeling occurring in pathologic circumstances drives disease progression by regulating cell-matrix interactions. The importance of matrix molecules to normal tissue functions is also highlighted by mutations in matrix genes that give rise to genetic disorders with diverse clinical phenotypes. In this review, we present critical and emerging issues related to matrix assembly in tissues and the multitasking roles for ECM in diseases such as osteoarthritis, fibrosis, cancer, and genetic diseases. The mechanisms underlying the various matrix-based diseases are also discussed. Research focused on the highly dynamic 3D ECM networks will help to discover matrix-related causative abnormalities of diseases as well as novel diagnostic tools and therapeutic targets.

Sox7 is involved in antibody-dependent endothelial cell activation and renal allograft injury via the Jagged1-Notch1 pathway

BACKGROUND

Antibody-mediated rejection (AMR) can cause graft loss and reduces long-term graft survival after kidney transplantation. Human leukocyte antigen (HLA) and/or non-HLA antibodies play a key role in the pathogenesis of AMR by targeting the allograft epithelium via complement activation and complement-independent mechanisms. However, the precise mechanisms of AMR remain unclear and treatment is still limited.

METHODS

In this study, we investigated the role of the endothelial-associated transcription factor Sox7 in AMR, using the anti-HLA antibody W6/32, shRNA-mediated Sox7 knockdown, and by manipulating the Notch pathway. We used an in vitro human kidney glomerular endothelial cells (HKGECs) model and an in vivo MHC-mismatched kidney transplantation model.

RESULTS

Sox7 expression was upregulated and the Jagged1-Notch1 pathway was activated in HKGECs after W6/32 activation. W6/32 antibodies increased the expression of adhesion molecules (VCAM-1, ICAM-1), inflammatory cytokines (IL-6, TNF-α), and chemokines (CXCL8, CXCL10), and Sox7 knockdown and inhibition of the Notch pathway by DAPT significantly reduced these effects. Jagged1 overexpression rescued the inhibitory effects of Sox7 knockdown. In addition, Sox7 knockdown attenuated acute allograft kidney injury in mice and reduced the expression of adhesion molecules and Jagged1-Notch1 signaling after transplantation.

CONCLUSIONS

Our findings suggest that Sox7 plays an important role in mediating HLA I antibody-dependent endothelial cell activation and acute kidney allograft rejection via the Jagged1-Notch1 pathway. Manipulating Sox7 in donor organs may represent a useful treatment for AMR in solid organ transplantation.

MicroRNA-212 promotes the recovery function and vascular regeneration of endothelial progenitor cells in mice with ischemic stroke through inactivation of the notch signaling pathway via downregulating MMP9 expression

Ischemic stroke is a refractory disease caused by cerebral ischemic injury, which results in brain dysfunction. This study intends to investigate the effects of microRNA-212 (miR-212) on the recovery function and vascular regeneration of endothelial progenitor cells (EPCs) by inactivation of the Notch signaling pathway by binding to matrix metallopeptidase 9 (MMP9) in mice with ischemic stroke. According to the results of database retrieval systems and data analysis, MMP9 was predicted as a gene related to ischemic stroke and miR-212 is a potential regulating mRNA of MMP9. All 72 healthy adult C57BL6 mice were selected for middle cerebral artery occlusion (MCAO) establishment. Cerebral infarction was observed under triphenyltetrazolium chloride staining. A series of inhibitors, activators, and siRNAs were introduced to the verified regulatory functions for miR-212 governing MMP9 in ischemic stroke. Cell proliferation was detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and tube-forming ability by tubule formation test. Reverse transcription quantitative polymerase chain reaction and Western blot analysis were used to detect the expressions of miR-212, MMP9, Hes-1, and Notch-1. The corresponding results demonstrated that the area of cerebral infarction and the number of neuronal necrosis increased in the MCAO group in contrast to the sham group. Meanwhile, upregulation of miR-212 or downregulation of MMP9 decreases the expressions of MMP9, Hes-1 Notch-1, increases cell proliferation and tube-forming ability and improves the pathological conditions of EPCs. Our study suggests that miR-212 promotes recovery function and vascular regeneration of EPCs through negative regulation of the Notch signaling pathway via downregulating expression of MMP9, thus provides a clinical theoretical basis for ischemic stroke therapy.

Association of urinary activity of MMP-9 with renal impairment in Mexican patients with type 2 diabetes mellitus

BACKGROUND

Diabetic kidney disease is the most common cause of chronic kidney disease (CKD). An early event in diabetic kidney disease is alteration of the glomerular basement membrane and the mesangial expansion. Matrix metalloproteinases (MMP) are a family of endopeptidases responsible for controlling the pathophysiological remodeling of tissues, including renal tissues. MMP-9 in human urine has been proposed as a marker of diabetic nephropathy and urinary tract infections (UTI).

METHODS

A cross-sectional study was conducted in type 2 diabetes mellitus (T2DM) patients who receive first level medical attention in Mexico. We used ELISA to measure MMP-9 levels in the urine of subjects with T2DM ≥ 18 years of age, who fulfilled the clinical requirements for calculation of glomerular filtration rate (GFR), according to the K/DOQI guide, in an attempt to identify whether MMP-9 levels in T2DM differ in patients with and without renal impairment. Univariate and multivariable analyses were performed in order to identify the association between MMP-9 and renal impairment.

RESULTS

Included in the study were 34 (45%) subjects with renal impairment and 42 (55%) without. In the group with renal impairment, 10 subjects corresponded to stages 1-2 and 24 subjects corresponded to stage 3, according to their values of GFR and urinary albumin, following that proposed by the K/DOQI. No differences were found relating to sex, age, having or not having a partner, education, being able to read and write a message and duration of T2DM. Moreover, no differences were found between the groups in terms of weight, height, body mass index, waist size in general and frequency of UTI. In contrast, serum creatinine and urinary albumin were higher in the group with renal impairment, while GFR was greater in the group without renal impairment. Levels of MMP-9 were greater in women compared to men. Through univariate analysis in the general population, the presence of MMP-9 and that of its percentile 90 (P90) P90 were associated with the renal impairment group; however, in patients without UTI, only the presence of MMP-9 was associated with the renal impairment group, and no association was found with its P90. Multivariate analysis revealed an association between MMP-9 and its P90 with renal impairment.

DISCUSSION

It is necessary to validate sensitive and non-invasive biological markers of CKD. We demonstrate that the presence and P90 of urinary MMP-9 are associated with renal impairment in Mexican patients with T2DM. While high levels of MMP-9 were associated to females and UTI, the presence of UTI was not associated with the incidence of renal impairment.

CCL25 chemokine-guided stem cell attraction: an assessment of possible benefits and risks

Due to its chemoattraction potential on mesenchymal stromal cells of the CCL25/CCR9 axis, local application of CCL25 to severely damaged tissues may be a promising approach for regenerative therapies. Analysis of the given data revealed that CCL25/CCR9 signaling has a crucial role in regulation of an adult immune homeostasis. CCR9 expression variations resulted in dysfunctional immune response in colitis, rheumatoid arthritis and endometriosis. Regarding oncology, different neoplastic tissues exploit CCL25-dependent CCR9 signaling for either local proliferation or migration processes. The CCR9 pathway likely can trigger crosstalk between the Akt and NOTCH pathway and thus participate in the regulation of the neoplastic behavior. In conclusion, the designated application-tissue requires precise molecular analysis of possible CCR9 expression due to its proto-oncogenic characteristics.

Reduction of Membrane Protein CRIM1 Decreases E-Cadherin and Increases Claudin-1 and MMPs, Enhancing the Migration and Invasion of Renal Carcinoma Cells

CRIM1 is a membrane protein that has been reported to be related to cell proliferation. CRIM1 is expressed in renal carcinoma cells, but its involvement in proliferation and malignant transformation remains unclear. We analyzed whether alterations in the characteristics of cancer cells are observed following knockdown of CRIM1. Decreased expression of CRIM1 did not affect proliferation or anchorage-independent growth. The results of wound healing and invasion assays showed that reduced expression of CRIM1 increased cells' migratory and invasive abilities. Expression analysis of factors involved in migration and invasion in CRIM1-knockdown cells revealed that expression of the cell adhesion factor E-cadherin declined and expression of claudin-1, which is upregulated in metastatic cancer cells, increased. In addition, increased expression of matrix metalloproteinase (MMP) 2 and MMP9, protease essential for cancer cell invasiveness, was observed. Furthermore, an increase in phosphorylated focal adhesion kinase (FAK), which increases cell migration, was observed. Increased expression of the E-cadherin transcription repressors Snail, Slug, and ZEB-1 were observed, and mRNA levels of E-cadherin were decreased. Therefore, expression of E-cadherin is thought to be decreased by both suppression of E-cadherin mRNA expression and promotion of degradation of the E-cadherin protein. In addition, expression of CRIM1 was decreased in renal cancer cells undergoing epithelial-mesenchymal transition (EMT) stimulated by tumor necrosis factor alpha (TNF-α). Thus, CRIM1 regulates the expression of several EMT-related factors and appears to play a role in suppressing migration and invasion through control of EMT.

The therapeutic potential of targeting the endothelial-to-mesenchymal transition

Endothelial cells (ECs) have been found to be capable of acquiring a mesenchymal phenotype through a process known as endothelial-to-mesenchymal transition (EndMT). First seen in the developing embryo, EndMT can be triggered postnatally under certain pathological conditions. During this process, ECs dedifferentiate into mesenchymal stem-like cells (MSCs) and subsequently give rise to cell types belonging to the mesoderm lineage. As EndMT contributes to a multitude of diseases, pharmacological modulation of the signaling pathways underlying EndMT may prove to be effective as a therapeutic treatment. Additionally, EndMT in ECs could also be exploited to acquire multipotent MSCs, which can be readily re-differentiated into various distinct cell types. In this review, we will consider current models of EndMT, how manipulation of this process might improve treatment of clinically important pathologies and how it could be harnessed to advance regenerative medicine and tissue engineering.

The apparent competitive action of ECM proteases and cross-linking enzymes during fibrosis: Applications to drug discovery

Progressive loss of organ function in most organs is associated with fibrosis, a tissue state associated with abnormal matrix buildup. If highly progressive, the fibrotic process eventually leads to organ failure and death. Fibrosis is a basic connective tissue lesion defined by the increase in the amount of fibrillar extracellular matrix (ECM) components in a tissue or organ. In addition, intrinsic changes in important structural cells can induce the fibrotic response by regulating the differentiation, recruitment, proliferation and activation of extracellular matrix-producing myofibroblasts. ECM enzymes belonging to the family of matrix metalloproteinases (MMPs) and lysyl oxidases (LOXs) play a crucial role in ECM remodeling and regeneration. MMPs have a catalytic role in degradation of ECM, whereas LOX/LOXLs mediate ECM, especially collagen, cross-linking and stiffening. Importantly, enzymes from both families are elevated during the fibrotic response to tissue injury and its resolution. Yet, the apparent molecular competition or antagonistic activities of these enzyme families during the various stages of fibrosis is often overlooked. In this review, we discuss the diverse roles of MMPs and LOX/LOXL2 in chronic organ fibrosis. Finally, we review contemporary therapeutic strategies for fibrosis treatment, based on neutralization of MMP and LOX activity, as well as the development of novel drug delivery approaches.

Circular RNA DLGAP4 Ameliorates Ischemic Stroke Outcomes by Targeting miR-143 to Regulate Endothelial-Mesenchymal Transition Associated with Blood-Brain Barrier Integrity

Circular RNAs (circRNAs) are highly expressed in the CNS and regulate physiological and pathophysiological processes. However, the potential role of circRNAs in stroke remains largely unknown. Here, we show that the circRNA DLGAP4 (circDLGAP4) functions as an endogenous microRNA-143 (miR-143) sponge to inhibit miR-143 activity, resulting in the inhibition of homologous to the E6-AP C-terminal domain E3 ubiquitin protein ligase 1 expression. circDLGAP4 levels were significantly decreased in the plasma of acute ischemic stroke patients (13 females and 13 males) and in a mouse stroke model. Upregulation of circDLGAP4 expression significantly attenuated neurological deficits and decreased infarct areas and blood-brain barrier damage in the transient middle cerebral artery occlusion mouse stroke model. Endothelial-mesenchymal transition contributes to blood-brain barrier disruption and circDLGAP4 overexpression significantly inhibited endothelial-mesenchymal transition by regulating tight junction protein and mesenchymal cell marker expression. Together, the results of our study are illustrative of the involvement of circDLGAP4 and its coupling mechanism in cerebral ischemia, providing translational evidence that circDLGAP4 serves as a novel therapeutic target for acute cerebrovascular protection.SIGNIFICANCE STATEMENT Circular RNAs (circRNAs) are involved in the regulation of physiological and pathophysiological processes. However, whether circRNAs are involved in ischemic injury, particularly cerebrovascular disorders, remains largely unknown. Here, we demonstrate a critical role for circular RNA DLGAP4 (circDLGAP4), a novel circular RNA originally identified as a sponge for microRNA-143 (miR-143), in ischemic stroke outcomes. Overexpression of circDLGAP4 significantly attenuated neurological deficits and decreased infarct areas and blood-brain barrier damage in the transient middle cerebral artery occlusion mouse stroke model. To our knowledge, this is the first report describing the efficacy of circRNA injection in an ischemic stroke model. Our investigation suggests that circDLGAP4 may serve as a novel therapeutic target for acute ischemic injury.

Urinary peptidomics analysis reveals proteases involved in diabetic nephropathy

Mechanisms underlying the onset and progression of nephropathy in diabetic patients are not fully elucidated. Deregulation of proteolytic systems is a known path leading to disease manifestation, therefore we hypothesized that proteases aberrantly expressed in diabetic nephropathy (DN) may be involved in the generation of DN-associated peptides in urine. We compared urinary peptide profiles of DN patients (macroalbuminuric, n = 121) to diabetic patients with no evidence of DN (normoalbuminuric, n = 118). 302 sequenced, differentially expressed peptides (adjusted p-value < 0.05) were analysed with the Proteasix tool predicting proteases potentially involved in their generation. Activity change was estimated based on the change in abundance of the investigated peptides. Predictions were correlated with transcriptomics (Nephroseq) and relevant protein expression data from the literature. This analysis yielded seventeen proteases, including multiple forms of MMPs, cathepsin D and K, kallikrein 4 and proprotein convertases. The activity of MMP-2 and MMP-9, predicted to be decreased in DN, was investigated using zymography in a DN mouse model confirming the predictions. Collectively, this proof-of-concept study links urine peptidomics to molecular changes at the tissue level, building hypotheses for further investigation in DN and providing a workflow with potential applications to other diseases.

TGF-β-Induced Endothelial-Mesenchymal Transition in Fibrotic Diseases

Fibrotic diseases are characterized by net accumulation of extracellular matrix proteins in affected organs leading to their dysfunction and ultimate failure. Myofibroblasts have been identified as the cells responsible for the progression of the fibrotic process, and they originate from several sources, including quiescent tissue fibroblasts, circulating CD34⁺ fibrocytes and the phenotypic conversion of various cell types into activated myofibroblasts. Several studies have demonstrated that endothelial cells can transdifferentiate into mesenchymal cells through a process termed endothelial- mesenchymal transition (EndMT) and that this can give rise to activated myofibroblasts involved in the development of fibrotic diseases. Transforming growth factor β (TGF-β) has a central role in fibrogenesis by modulating the fibroblast phenotype and function, inducing myofibroblast transdifferentiation and promoting matrix accumulation. In addition, TGF-β by inducing EndMT may further contribute to the development of fibrosis. Despite extensive investigation of the pathogenesis of fibrotic diseases, no effective treatment strategies are available. Delineation of the mechanisms responsible for initiation and progression of fibrotic diseases is crucial for the development of therapeutic strategies for the treatment of the disease. In this review, we summarize the role of the TGF-β signaling pathway and EndMT in the development of fibrotic diseases and discuss their therapeutic potential.

Tiron ameliorates oxidative stress and inflammation in titanium dioxide nanoparticles induced nephrotoxicity of male rats

Although the widespread use of titanium dioxide nanoparticles (TiO₂ NPs), few studies were conducted on its hazard influence on human health. Tiron a synthetic vitamin E analog was proven to be a mitochondrial targeting antioxidant. The current investigation was performed to assess the efficacy of tiron against TiO₂ NPs induced nephrotoxicity. Eighty adult male rats divided into four different groups were used: group I was the control, group II received TiO2 NPs (100mg\Kg BW), group III received TiO2 NPs plus tiron (470mg\kg BW), and group IV received tiron alone. Urea, creatinine and total protein concentrations were measured in serum to assess the renal function. Antioxidant status was estimated by determining the activities of glutathione peroxidase, superoxide dismutase, malondialdehyde (MDA) level and glutathione concentration in renal tissue. As well as Renal fibrosis was evaluated though measuring of transforming growth factor-β1 (TGFβ1) and matrix metalloproteinase 9 (MMP9) expression levels and histopathological examination. TiO₂ NPs treated rats showed marked elevation of renal indices, depletion of renal antioxidant enzymes with marked increase in MDA concentration as well as significant up-regulation in fibrotic biomarkers TGFβ1 and MMP9. Oral administration of tiron to TiO₂ NPs treated rats significantly attenuate the renal dysfunction through decreasing of renal indices, increasing of antioxidant enzymes activities, down-regulate the expression of fibrotic genes and improving the histopathological picture for renal tissue. In conclusion, tiron was proved to attenuate the nephrotoxicity induced by TiO₂ NPs through its radical scavenging and metal chelating potency.

Matrix metalloproteinases in ureteropelvic junction obstruction

BACKGROUND

Management of ureteropelvic junction obstruction (UPJO) remains controversial. The aim of the present study was to measure the levels of matrix metalloproteinases (MMPs) in UPJO patients who were planned to undergo surgery and thus clarify if MMPs levels could serve as potential biomarkers of surgical obstruction in UPJO.

METHODS

Serum samples of infants with UPJO diagnosis were compared to serum samples of healthy age-matched controls. MMP2 and MMP9 were quantified using enzyme-linked immunosorbent assay (ELISA).

RESULTS

A total of 17 infants with UPJO diagnosis, and median age 1.5 months, were prospectively recruited. MMP9 levels were significantly decreased in the serum samples of UPJO infants compared to controls (p =0.037). Also MMP2 values were higher in UPJO infants compared to controls, but the difference was not statistically significant (p =0.206).

CONCLUSIONS

This study found decreased concentrations of MMP9 in infants with obstructive hydronephrosis. However, the results should be tested in larger population samples and even be evaluated simultaneously with urine samples in order to delineate the ability of MMPs to serve as obstruction biomarkers. HIPPOKRATIA 2017, 21(3): 136-139.

Nucleotides and nucleoside signaling in the regulation of the epithelium to mesenchymal transition (EMT)

The epithelium-mesenchymal transition (EMT) is an important process of cell plasticity, consisting in the loss of epithelial identity and the gain of mesenchymal characteristics through the coordinated activity of a highly regulated informational program. Although it was originally described in the embryonic development, an important body of information supports its role in pathology, mainly in cancerous and fibrotic processes. The purinergic system of inter-cellular communication, mainly based in ATP and adenosine acting throughout their specific receptors, has emerged as a potent regulator of the EMT in several pathological entities. In this context, cellular signaling associated to purines is opening the understanding of a new element in the complex regulatory network of this phenotypical differentiation process. In this review, we have summarized recent information about the role of ATP and adenosine in EMT, as a growing field with high therapeutic potential.