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Matrix metalloproteinases (MMPs) are zinc-dependent endoproteases responsible for the metabolism of extracellular matrix (ECM). MMPs can degrade the various ECM components as a variety of non-ECM molecules. Hyperactivity of MMPs and improper regulation or inhibition could lead to certain disorders, like non-healing chronic wounds. In chronic wounds, unlike in acute ones, there are always higher levels of MMPs due to the accompanying inflammation. Different proteases are responsible for this condition; nonetheless, blocking MMPs can help restore the wound's healing ability. The level of MMPs can help indicate the prognosis of chronic wounds. In some cases, the healing process is delayed by microbial wound infections. Bacterial proteases may up-regulate the levels of MMPs produced by host cells. That means that both host MMPs as proteases secreted by the infecting bacteria need to be targeted to increase the healing capacity of the wound. MMPs activity modulating treatments by superabsorbent polymer dressings can improve healing rates of chronic wounds. The main goal of this review was presentation the specific role of metalloproteinases in the pathology and therapy of hard-to-heal wounds.

Recent evidence points at the role that human endogenous retroviruses (HERVs) may play through the activation of genes integrated across the human genome. Although a variety of genetic/epigenetic mechanisms maintain most HERVs silenced, independent environmental stimuli including infections may transactivate endogenous elements favoring pathogenic conditions. Several studies associated exposures to Mycobacterium avium subsp. paratuberculosis (MAP) with increased anti-MAP seroreactivity in T1D patients. Here, we assessed humoral responses against HERV envelope antigens (HERV-K Env and HERV-W Env ) and four MAP-derived peptides with human homologs in distinct populations: Sardinian children at T1D risk (rT1D) (n = 14), rT1D from mainland Italy (n = 54) and Polish youths with T1D (n = 74) or obesity unrelated to autoimmunity (OB) (n = 26). Unlike Sardinian rT1D, youths displayed increased anti-HERV-W Env Abs prevalence compared to age-matched OB or healthy controls (24.32 vs. 11.54%, p = 0.02 for Polish T1D/OB and 31.48 vs. 11.90%, p = 0.0025 for Italian rT1D). Anti-HERV-K Env responses showed variable trends across groups. A strong correlation between Abs levels against HERV-W Env and homologous peptides was mirrored by time-related Abs patterns. Elevated values registered for HERV-W Env overlaped with or preceded the detection of T1D diagnostic autoantibodies. These results support the hypothesis of MAP infection leading to HERV-W antigen expression and enhancing the production of autoantibodies in T1D.

Background: Matrix metalloproteinases (MMP) and tissue inhibitors of metalloproteinases (TIMP) are involved in cardiovascular remodeling in hypertension. Because metabolic abnormalities typical of metabolic syndrome is the dominant phenotype of primary hypertension in children, we hypothesized that MMP-9 and TIMP-1 plasma concentrations are altered in hypertensive children and correlate with metabolic abnormalities and target organ damage., Method: A total of 109 children (15.6, 10-17 years) with untreated primary hypertension were included to the study. The control group consisted of 74 healthy, normotensive children., Results: Plasma MMP-9, TIMP-1 concentrations, and MMP-9/TIMP-1 ratio were significantly elevated in hypertensive boys in comparison with normotensive boys (P = 0.0001, P = 0.04, and P = 0.001, respectively), whereas there were no differences between hypertensive and normotensive girls. The levels of MMP-9 and TIMP-1 as well as MMP-9/TIMP-1 ratio were not associated either with hypertension stage, left ventricular hypertrophy, or carotid intima-media thickness. However, in a subgroup of 30 hypertensive patients in whom arterial stiffness was measured, TIMP-1 concentrations correlated with aortic pulse pressure (P < 0.05; r = 0.367), augmentation pressure (P < 0.05; r = 0.428), and augmentation index (P < 0.05; r = 0.404).Only hypertensive boys presented negative correlations of both MMP-9 and TIMP-1 levels with high-density lipoprotein cholesterol (r = -0.254, P = 0.01 and r = -0.241, P = 0.02, respectively)., Conclusion: Hypertensive boys but not girls had elevated MMP-9 and TIMP-1 plasma concentrations, which indicates sex-related role of MMP/TIMP system in pediatric hypertension. The correlation between serum TIMP-1 and markers of arterial stiffness indicates on the involvement of TIMPs in arterial remodeling.

The aim of the study was to find out whether peripheral blood leukocyte adiponectin receptors 1 and 2 (AdipoR1, AdipoR2) protein expression patterns (flow cytometry) differ between the primary hypertension children (n = 57) and healthy controls (n = 19) and if their expression levels are related to selected clinical parameters. The group of 26 patients [AdipoR(-)] showed lower and the group of 31 patients [AdipoR(+)] showed higher AdipoRs protein expression than the control and each other (P < 0.01 for neutrophils, P < 0.05 for monocytes). The AdipoR(+) leukocytes expressed higher AdipoR1 mRNA levels (RT-PCR) than AdipoR(-) ones and controls (P = 0.022 and P = 0.007, resp.). Despite greater BMI, the AdipoR(-) patients had unchanged serum adiponectin levels. In contrast, AdipoR(+) patients had lower serum adiponectin concentrations than the AdipoR(-) ones and controls (P < 0.001). The AdipoR(+) patients had higher blood pressure (P = 0.042) and greater carotid intima-media thickness (P = 0.017) than the AdipoR(-) ones. The stage of hypertension was associated with increased neutrophil but not monocyte AdipoR1 density (AdipoR1 MFI) (P < 0.05). Severe ambulatory hypertension was presented more often in AdipoR(+) patients than in AdipoR(-) ones (51.6% versus 26.9%, resp.; P < 0.01). In conclusion, neutrophil AdipoRs upregulation was associated with early stages of vascular injury, hypertension severity, and low serum levels of adiponectin.

Renin-angiotensin system, metabolic abnormalities, and immune activity have a role in the pathogenesis of primary hypertension. We assessed the leukocyte mRNA expression of angiotensinogen, angiotensin converting enzyme, renin, angiotensin 2 type 1 receptor, CD14 molecule, adiponectin type 1 receptor, and leptin receptor in hypertensive children before and after nonpharmacological treatment. Leukocyte mRNA expression was measured by means of quantitative real-time reverse transcriptase-polymerase chain reaction in 23 hypertensive children before and after 6 months of nonpharmacological treatment based on dietary advice and physical activities. Twenty-three normotensive children matched for age, sex, and body mass index served as a control group. Before treatment patients had elevated expression of angiotensin converting enzyme and CD14 mRNA, decreased expression of angiotensinogen and angiotensin type 1 receptor mRNA, and unchanged expression of renin, adiponectin, and leptin receptors mRNA as compared with controls. Renin mRNA negatively correlated with 24-hour mean arterial pressure and carotid intima-media thickness. Six months of nonpharmacological treatment caused decrease of blood pressure and normalization of metabolic abnormalities. Renin, adiponectin, and leptin receptors mRNA expression decreased and were lower than in control group. Changes in blood pressure, left ventricular mass, carotid intima-media thickness, body mass index, and waist circumference did not correlate with changes in the expression of renin-angiotensin system genes, CD14, leptin, and adiponectin receptors mRNA. We conclude that leukocytes of hypertensive children displayed alterations in the expression of renin-angiotensin system genes as well as those of CD14. Nonpharmacological treatment resulted in downregulation of genes involved in renin-angiotensin activation and those engaged in leukocyte responses to adipokines.

The family of insulin receptor substrates (IRS) consists of four proteins (IRS-1-IRS-4), which were initially characterized as typical cytosolic adaptor proteins involved in insulin receptor (IR) and insulin-like growth factor I receptor (IGF-IR) signaling. The first cloned and characterized member of the IRS family, IRS-1, has a predicted molecular weight of 132 kDa, however, as a result of its extensive serine phosphorylation it separates on a SDS gel as a band of approximately 160-185 kDa. In addition to its metabolic and growth-promoting functions, IRS-1 is also suspected to play a role in malignant transformation. The mechanism by which IRS-1 supports tumor growth is not fully understood, and the argument that IRS-1 merely amplifies the signal from the IGF-1R and/or IR requires further investigation. Almost a decade ago, we reported the presence of nuclear IRS-1 in medulloblastoma clinical samples, which express viral oncoprotein, large T-antigen of human polyomavirus JC (JCV T-antigen). This first demonstration of nuclear IRS-1 was confirmed by several other laboratories. Nuclear IRS-1 was also detected by cells expressing the SV40 T-antigen, v-Src, in immortalized fibroblasts stimulated with IGF-I, in hepatocytes, 32D cells, and in an osteosarcoma cell line. More recently, nuclear IRS-1 was detected in breast cancer cells in association with estrogen receptor alpha (ERα), and in JC virus negative medulloblastoma cells expressing estrogen receptor beta (ERβ), further implicating nuclear IRS-1 in cellular transformation. Here, we discuss how nuclear IRS-1 acting on DNA repair fidelity, transcriptional activity, and cell growth can support tumor development and progression., (Copyright © 2011 Wiley Periodicals, Inc.)

Matrix metalloproteinases (MMPs), also known as matrixins are endoproteinases that degrading protein components of the extracellular matrix (ECM), cause its restoration and reconstruction. In this way, retain the appropriate structure of the ECM and basement membrane during both: physiological processes and pathological conditions. Changes in the structure of the ECM are accompanied by physiological processes such as embryogenesis, angiogenesis, apoptosis, and development and rebuilding of connective tissue. Under physiological conditions, the activity of MMPs is regulated at the transcriptional level, activation of proMMP precursor zymogens and interactions with endogenous inhibitors (tissue inhibitors of metalloproteinases, TIMPs). The imbalance in the system of MMPs/TIMPs induces the development of many diseases, including cancer, fibrosis, arthritis, cardiovascular diseases, neurological and autoimmune disorders. The publication describes the types of metalloproteinases, their structure, function and regulation of activity and endogenous inhibitors of MMPs.

The large T-antigen from human polyomavirus JC (JCV T-antigen) is suspected to play a role in malignant transformation. Previously, we reported that JCV T-antigen requires the presence of a functional insulin-like growth factor I receptor (IGF-IR) for transformation of fibroblasts and for survival of medulloblastoma cell lines; that IGF-IR is phosphorylated in medulloblastoma biopsies and that JCV T-antigen inhibits homologous recombination-directed DNA repair, causing accumulation of mutations. Here we are evaluating whether JCV T-antigen positive and negative mouse medulloblastoma cell lines, which significantly differ in their tumorigenic properties, are also different in their abilities to repair double strand breaks of DNA (DSBs). Our results show that despite much stronger tumorigenic potential, JCV T-antigen positive medulloblastoma cells are more sensitive to genotoxic agents (cisplatin and gamma-irradiation). Subsequent analysis of DNA repair of DSBs indicated that homologous recombination-directed DNA repair (HRR) was selectively attenuated in JCV T-antigen positive medulloblastoma cells. JCV T-antigen did not affect HRR directly. In the presence of JCV T-antigen, insulin receptor substrate 1 (IRS-1) translocated to the nucleus where it co-localized with Rad51, possibly attenuating HRR., (Copyright (c) 2006 Wiley-Liss, Inc.)

The progression of cancer is often associated with genomic instability, which may develop as a result of compromised defense mechanisms responsible for the maintenance of chromosomal integrity. These include defects in telomere preservation, chromosomal segregation, and DNA repair. In this review, we discuss molecular interactions between viral and cellular signaling components, which interfere with DNA repair mechanisms, and possibly contribute to the development of a mutagenic phenotype. Our studies indicate that large T-antigen from the human polyomavirus JC (JCV T-antigen) inhibits homologous recombination directed DNA repair (HRR)-causing accumulation of mutations in the affected cells (JCP 2005, in press). Surprisingly, T-antigen does not operate directly, but utilizes insulin receptor substrate 1 (IRS-1), which is the major signaling molecule for insulin-like growth factor I receptor (IGF-IR). Following T-antigen-mediated nuclear translocation, IRS-1 binds Rad51 at the site of damaged DNA. This T-antigen-mediated inhibition of HRR does not function in cells lacking IRS-1, and can be reproduced in the absence of T-antigen by IRS-1 with an artificial nuclear localization signal. The interplay described between the IGF-IR signaling system and JCV T-antigen in the process of DNA repair could be relevant, since nearly 90% of the human population is seropositive for JC virus, JCV T-antigen transforms cells in vitro, is tumorigenic in experimental animals, and the presence of JC virus has been shown in an increasing number of biopsies of human cancer., (Copyright (c) 2005 Wiley-Liss, Inc.)

JC polyomavirus (JCV), which infects 90% of the human population, is detectable in human tumors. Its early protein, JCV T-antigen, transforms cells in vitro and is tumorigenic in experimental animals. Although T-antigen-mediated transformation involves genetic alterations of the affected cells, the mechanism underlying this genomic instability is not known. We show that JCV T-antigen inhibits homologous recombination DNA repair (HRR), which results in an accumulation of mutations. T-antigen does not operate directly but utilizes a cytosolic molecule, insulin receptor substrate 1 (IRS-1). Following T-antigen-mediated nuclear translocation, IRS-1 binds Rad51 at the site of damaged DNA. This T-antigen-mediated inhibition of HRR does not function in cells lacking IRS-1, and can be reproduced in the absence of T-antigen by IRS-1 with artificial nuclear localization signal. Our observations define a new mechanism by which viral protein utilizes cytosolic molecule to inhibit faithful DNA repair, and suggest how polyomaviruses could compromise stability of the genome. (c) 2005 Wiley-Liss, Inc.

During metastases, cancer cells are temporarily exposed to the condition in which interactions with extracellular environment can be restricted (anchorage-independence). We demonstrate that the sensitivity of prostate cancer cell lines, DU145 and PC-3, to genotoxic treatment (cisplatin and gamma-irradiation) increased several folds when cells were forced to grow in anchorage-independence. This enhanced drug sensitivity was associated with a severe impairment of homologous recombination-directed DNA repair (HRR). The mechanism involves Rad51, which is the major enzymatic component of HRR. The protein level of Rad51 and its recruitment to DNA double-strand breaks (DSBs) were both attenuated. Rad51 deficiency in anchorage-independence was not associated with Rad51 promoter activity, and was not compensated by a constitutive overexpression of Rad51 cDNA. Instead, Rad51 protein level and its ability to colocalize with DSBs were restored in the presence of proteosome inhibitors, or when cells from the suspension cultures were allowed reattachment. Presented results indicate that anchorage-independence sensitizes prostate cancer cells to genotoxic agents; however, it also attenuates faithful component of DNA repair by targeting stability of Rad51. This temporal attenuation of HRR may contribute to the accumulation mutations after DNA damage, and possibly the selection of new adaptations in cells, which survived genotoxic treatment.

Polyomaviruses are highly suspected to be involved in the development of cancer. A strong correlation has been established between the activity of an early viral genome and the development of a transformed phenotype. Polyomavirus transforming antigens (T-antigens) are the major suspects in the process of deregulating cellular equilibrium. Multiple interactions between T-antigens and cellular regulatory proteins have been detected at different regulatory levels including signal transduction, gene expression, cell cycle progression, and possible DNA repair. In this context, we are reviewing the most recent experimental evidence which, in combination with more than thirty years of studies of polyomaviruses, could help us understand whether and how viral infection contributes to the development of malignant transformation.

The receptor for insulin-like growth factor I (IGF-IR) controls normal and pathological growth of cells. DNA repair pathways represent an unexplored target through which the IGF-IR signaling system might support pathological growth leading to cellular transformation. However, this study demonstrates that IGF-I stimulation supports homologous recombination-directed DNA repair (HRR). This effect involves an interaction between Rad51 and the major IGF-IR signaling molecule, insulin receptor substrate 1 (IRS-1). The binding occurs within the cytoplasm, engages the N-terminal domain of IRS-1, and is attenuated by IGF-I-mediated IRS-1 tyrosine phosphorylation. In the absence of IGF-I stimulation, or if mutated IGF-IR fails to phosphorylate IRS-1, localization of Rad51 to the sites of damaged DNA is diminished. These results point to a direct role of IRS-1 in HRR and suggest a novel role for the IGF-IR/IRS-1 axis in supporting the stability of the genome.

Phosphotyrosine was found to be 0.5% of the total phosphoamino acids labelled with [32P]orthophosphate in endogenous maize seedlings proteins. Two peaks of protein kinase activity towards phosphorylation of synthetic peptide poly (Glu80, Tyr20) were obtained after chromatography of protein extract of dark-grown etiolated maize seedlings on phosphocellulose. The phosphorylation of synthetic peptide as well as endogenous proteins was strongly stimulated by Mn2+. At least three endogenous proteins with molecular masses in the range of 40-65 kDa were predominantly phosphorylated. This phosphorylation was resistant to alkali treatment. Chemical, immunological and enzymatic data indicated the presence of tyrosine kinase activity and also phosphotyrosine in proteins of maize seedlings. The plant enzyme(s) is reminiscent known mammalian cytosolic tyrosine kinase(s).