Endopeptidase Research Articles

Genetic interaction mapping reveals functional relationships between peptidoglycan endopeptidases and carboxypeptidases.

Peptidoglycan (PG) is the main component of the bacterial cell wall; it maintains cell shape while protecting the cell from internal osmotic pressure and external environmental challenges. PG synthesis is essential for bacterial growth and survival, and a series of PG modifications are required to allow expansion of the sacculus. Endopeptidases (EPs), for example, cleave the crosslinks between adjacent PG strands to allow the incorporation of newly synthesized PG. EPs are collectively essential for bacterial growth and must likely be carefully regulated to prevent sacculus degradation and cell death. However, EP regulation mechanisms are poorly understood. Here, we used TnSeq to uncover novel EP regulators in Vibrio cholerae. This screen revealed that the carboxypeptidase DacA1 (PBP5) alleviates EP toxicity. dacA1 is essential for viability on LB medium, and this essentiality was suppressed by EP overexpression, revealing that EP toxicity both mitigates, and is mitigated by, a defect in dacA1. A subsequent suppressor screen to restore viability of ΔdacA1 in LB medium identified hypomorphic mutants in the PG synthesis pathway, as well as mutations that promote EP activation. Our data thus reveal a more complex role of DacA1 in maintaining PG homeostasis than previously assumed.

Exploring bi-carbazole-linked triazoles as inhibitors of prolyl endo peptidase via integrated in vitro and in silico study

A serine protease called prolyl endopeptidase (PEP) hydrolyses the peptide bonds on the carboxy side of the proline ring. The excessive PEP expression in brain results in neurodegenerative illnesses like dementia, Alzheimer’s disease, and Parkinson's disease. Results of the prior studies on antioxidant activity, and the non-cytotoxic effect of bi-carbazole-linked triazoles, encouraged us to extend our studies towards its anti-diabetic potential. Hence, for this purpose all compounds 1–9 were evaluated to reveal their anti-prolyl endo peptidase activity. Fortunately, seven compounds resulted into significant inhibitory capability ranging from 26 to 63 µM. Among them six compounds 4–9 exhibited more potent inhibitory activity with IC50 values 46.10 ± 1.16, 42.30 ± 1.18, 37.14 ± 1.21, 26.29 ± 0.76, 28.31 ± 0.64 and 31.11 ± 0.84 µM respectively, while compound 3 was the least active compound in the series with IC50 value 63.10 ± 1.58 µM comparing with standard PEP inhibitor bacitracin (IC50 = 125 ± 1.50 µM). Moreover, mechanistic study was performed for the most active compounds 7 and 8 with Ki values 24.10 ± 0.0076 and 23.67 ± 0.0084 µM respectively. Further, the in silico studies suggested that the compounds exhibited potential interactions and significant molecular conformations, thereby elucidating the structural basis for their inhibitory effects.

Establishment of FAP-overexpressing Cells for FAP-targeted Theranostics.

Fibroblast activation protein (FAP) has been widely studied and exploited for its clinical applications. One of the difficulties in interpreting reports of FAP-targeted theranostics is due to the lack of accurate controls, making the results less specific and less confirmative. This study aimed to establish a pair of cell lines, in which one highly expresses FAP (HT1080-hFAP) and the other has no detectable FAP (HT1080-vec) as control, to accurately evaluate the specificity of the FAP-targeted theranostics in vitro and in vivo. The cell lines of the experimental group (HT1080-hFAP) and no-load group (HT1080-vec) were obtained by molecular construction of the recombinant plasmid pIRES-hFAP. The expression of hFAP in HT1080 cells was detected by PCR, Western blotting and flow cytometry. CCK-8, Matrigel transwell invasion assay, scratch test, flow cytometry and immunofluorescence were used to verify the physiological function of FAP. The activities of human dipeptidyl peptidase (DPP) and human endopeptidase (EP) were detected by ELISA in HT1080-hFAP cells. PET imaging was performed in bilateral tumor-bearing nude mice models to evaluate the specificity of FAP. RT-PCR and Western blotting demonstrated the mRNA and protein expression of hFAP in HT1080-hFAP cells but not in HT1080-vec cells. Flow cytometry confirmed that nearly 95% of the HT1080-hFAP cells were FAP positive. The engineered hFAP on HT1080 cells had its ability to retain enzymatic activities and a variety of biological functions, including internalization, proliferation-, migration-, and invasion-promoting activities. The HT1080-hFAP xenografted tumors in nude mice bound and took up 68GA-FAPI-04 with superior selectivity. High image contrast and tumor-organ ratio were obtained by PET imaging. The HT1080-hFAP tumor retained the radiotracer for at least 60 min. This pair of HT1080 cell lines was successfully established, making it feasible for accurate evaluation and visualization of therapeutic and diagnostic agents targeting the hFAP.

Mechanistic Insights into the Activities of Major Families of Enzymes in Bacterial Peptidoglycan Assembly and Breakdown.

Serving as an exoskeletal scaffold, peptidoglycan is a polymeric macromolecule that is essential and conserved across all bacteria, yet is absent in mammalian cells; this has made bacterial peptidoglycan a well-established excellent antibiotic target. In addition, soluble peptidoglycan fragments derived from bacteria are increasingly recognised as key signalling molecules in mediating diverse intra- and inter-species communication in nature, including in gut microbiota-host crosstalk. Each bacterial species encodes multiple redundant enzymes for key enzymatic activities involved in peptidoglycan assembly and breakdown. In this review, we discuss recent findings on the biochemical activities of major peptidoglycan enzymes, including peptidoglycan glycosyltransferases (PGT) and transpeptidases (TPs) in the final stage of peptidoglycan assembly, as well as peptidoglycan glycosidases, lytic transglycosylase (LTs), amidases, endopeptidases (EPs) and carboxypeptidases (CPs) in peptidoglycan turnover and metabolism. Biochemical characterisation of these enzymes provides valuable insights into their substrate specificity, regulation mechanisms and potential modes of inhibition.

Zinc oxide nanoparticles mediated biostimulant impact on cadmium detoxification and in silico analysis of zinc oxide-cadmium networks in Zea mays L. regulome

Cadmium (Cd) toxicity can significantly limit plant growth and development. To eliminate the toxic effects of Cd stress, we intended to evaluate the biochemical mediated physiological responses in maize treated with biostimulant and zinc oxide nanoparticles (ZnPs). In silico analysis exhibited that the maize treated with Cd stress (200 μM) had an adverse impact on CAT1, CAT2, CAT3 and gor1 proteins, which are influential in managing the machinery of redox homeostasis. While maize inoculated with bacteria-based biostimulant and ZnPs (10 ppm) showed prominently improved biomass, chlorophyll a, b and carotenoid content. We found a significant increase in the total sugar, protein, proline content and antioxidants under the effect of Cd stress. However, these parameters are further enhanced by applying biostimulants and ZnPs. Declined lipid peroxidation and membrane solubilization index under the effect of biostimulant and ZnPs was observed. Furthermore, these treatments improved maize's zinc, copper, sodium, magnesium, iron, potassium and calcium content. Based on these results, an antagonistic relationship between Zn and Cd uptake that triggered efficient Cd detoxification in maize shoot was found. Scanning electron micrography showed distorted leaf structure of the Cd stressed plants while the biostimulant and ZnPs reduced the structural cell damage of maize leaves. In silico study showed that ZnO positively regulates all protein interactors, including GRMZM2G317386_P01 (Metallo endo proteinase 1-MMP), GRMZM2G110220_P01 (Metallo endo proteinase 5-MMP), GRMZM2G103055_P01 (Alpha-amylase) and GRMZM2G006069_P01 (Zn-dependent exo peptidase superfamily) proteins which are involved in energy generating processes, channels formation, matrix re-localization and stress response. This suggests that ZnO offers an ideal role with protein interactors in maize. Our findings depict that these treatments, i.e., biostimulant and ZnPs alone, are efficient enough to exhibit Cd remediation potential in maize; however, their combination showed synergistic effects.

Post-anthesis moderate soil-drying facilitates source-to-sink remobilization of nitrogen via redistributing cytokinins in rice

This study investigated if and how cytokinins would mediate the effect of post-anthesis soil-drying on source-to-sink remobilization of nitrogen (N) in rice. Field experiments were conducted with normal (NN) and high amount of N (HN) applications. Two irrigation regimes, well-watered (WW) and moderate soil-drying (MD), were imposed from 8 days after full heading until maturity. The results showed that N use efficiency (NUE) including internal N use efficiency, N partial factor productivity and N harvest index, was substantially increased in MD relative to in WW. The MD promoted the reallocation and transfer of N, free amino acids (FAAs) and trans-zeatin (Z) + trans-zeatin riboside (ZR) from the source organs (stems and leaves) to the sink organ (panicles). Activities of protein degradation enzymes including endopeptidase (EP) and aminopeptidase (AP) in stems and leaves, and expression levels of FAAs transporter genes in panicles were substantially increased in MD than in WW, and were closely associated with Z + ZR content there. Application of kinetin to stems and leaves significantly decreased the activities of EP and AP, resulting in more N retention in stems and leaves and lower N harvest index. Application of kinetin to panicles significantly increased the expression levels of FAAs transporter genes in panicles, leading to less N retention in stems and leaves and higher N harvest index. Such facilitation in source-to-sink remobilization of N induced by the MD was greater at HN than at NN. Collectively, a post-anthesis MD can enhance source-to-sink remobilization of N and synergistically increase grain yield and NUE via redistributing cytokinins (Z + ZR) in rice.

Trace elements and the carotid plaque: the GOOD (Mg, Zn, Se), the UGLY (Fe, Cu), and the BAD (P, Ca)?

Multiple epidemiological studies have suggested that industrialization and progressive urbanization should be considered one of the main factors responsible for the rising of atherosclerosis in the developing world. In this scenario, the role of trace metals in the insurgence and progression of atherosclerosis has not been clarified yet. In this paper, the specific role of selected trace elements (magnesium, zinc, selenium, iron, copper, phosphorus, and calcium) is described by focusing on the atherosclerotic prevention and pathogenesis plaque. For each element, the following data are reported: daily intake, serum levels, intra/extracellular distribution, major roles in physiology, main effects of high and low levels, specific roles in atherosclerosis, possible interactions with other trace elements, and possible influences on plaque development. For each trace element, the correlations between its levels and clinical severity and outcome of COVID-19 are discussed. Moreover, the role of matrix metalloproteinases, a family of zinc-dependent endopeptidases, as a new medical therapeutical approach to atherosclerosis is discussed. Data suggest that trace element status may influence both atherosclerosis insurgence and plaque evolution toward a stable or an unstable status. However, significant variability in the action of these traces is evident: some - including magnesium, zinc, and selenium - may have a protective role, whereas others, including iron and copper, probably have a multi-faceted and more complex role in the pathogenesis of the atherosclerotic plaque. Finally, calcium and phosphorus are implicated in the calcification of atherosclerotic plaques and in the progression of the plaque toward rupture and severe clinical complications. In particular, the role of calcium is debated. Focusing on the COVID-19 pandemia, optimized magnesium and zinc levels are indicated as important protective tools against a severe clinical course of the disease, often related to the ability of SARS-CoV-2 to cause a systemic inflammatory response, able to transform a stable plaque into an unstable one, with severe clinical complications.

Biochemical Toxicity and Potential Detoxification Mechanisms in Earthworms Eisenia fetida Exposed to Sulfamethazine and Copper.

The present study investigated the biochemical toxicity and potential detoxification mechanisms in earthworms Eisenia fetida exposed to sulfamethazine (SMZ) (7.5, 15 and 30 mg kg-1) either alone or in combination with Copper (Cu) (100 mg kg-1) in soil. The results showed that increasing concentrations of SMZ in soil activated superoxide dismutase, catalase and glutathione peroxidase isozymes, suggesting reactive oxygen species (ROS) burst in earthworms. Treatment with SMZ and Cu separately or in combination caused protein oxidation and damage, elevating the synthesis of ubiquitin, the 20S proteasome, cytochrome P450 (CYP450), and heat shock protein 70 (HSP70). Such treatments also induced the activities of proteases, endoproteinase (EP) and glutathione S-transferases (GSTs). The results suggested that the ubiquitin-20S proteasome, proteases, EP and HSP70 were involved in degradation or remediation of oxidatively damaged proteins. Elevated levels of CYP450 and GSTs also participated in the detoxification of the earthworms.

Knockout of the RAS endoprotease RCE1 accelerates myeloid leukemia by downregulating GADD45b.

Knockout of the RAS endoprotease RCE1 accelerates myeloid leukemia by downregulating GADD45b.

Structural basis of peptidoglycan endopeptidase regulation

Most bacteria surround themselves with a cell wall, a strong meshwork consisting primarily of the polymerized aminosugar peptidoglycan (PG). PG is essential for structural maintenance of bacterial cells, and thus for viability. PG is also constantly synthesized and turned over; the latter process is mediated by PG cleavage enzymes, for example, the endopeptidases (EPs). EPs themselves are essential for growth but also promote lethal cell wall degradation after exposure to antibiotics that inhibit PG synthases (e.g., β-lactams). Thus, EPs are attractive targets for novel antibiotics and their adjuvants. However, we have a poor understanding of how these enzymes are regulated in vivo, depriving us of novel pathways for the development of such antibiotics. Here, we have solved crystal structures of the LysM/M23 family peptidase ShyA, the primary EP of the cholera pathogen Vibrio cholerae Our data suggest that ShyA assumes two drastically different conformations: a more open form that allows for substrate binding and a closed form, which we predicted to be catalytically inactive. Mutations expected to promote the open conformation caused enhanced activity in vitro and in vivo, and these results were recapitulated in EPs from the divergent pathogens Neisseria gonorrheae and Escherichia coli Our results suggest that LysM/M23 EPs are regulated via release of the inhibitory Domain 1 from the M23 active site, likely through conformational rearrangement in vivo.

Influence of proteasome activator γ on iodine uptake capability of anaplastic thyroid carcinoma

Objective To investigate the changes of iodine uptake capability (IUC) and mRNA expression of iodine uptake-related proteins in ARO and WRO thyroid carcinoma cell lines after silence of proteasome activator γ (REGγ), and observe the relation between REGγ and IUC of thyroid carcinoma. Methods The AROshN, AROshR, WROshN and WROshR (shN= blank plasmid, shR=plasmid with silence of REGγ) thyroid carcinoma cell lines were routinely cultured. Low dosage (3.7 kBq) of Na125I was added and then IUC was determined at different time points (5, 10, 15, 20, 40 and 70 min). The mRNA expressions of sodium/iodine symporter (NIS), thyroid stimulating hormone receptor (TSHR), thyroid peroxidase (TPO) and thyroglobulin (Tg) were examined by real-time PCR. Paired t test was used to analyze the data. Results After the silence of REGγ, the peak values of IUC in AROshR and WROshR cells were increased from (1 974±12) to (4 502±23) counts/min, and from (2 988±25) to (5 001±16) counts/min, respectively. The increase rates were 128.1% in AROshR cells and 67.4% in WROshR cells (t values: 17.30, 13.20, both P<0.05). The mRNA expressions of NIS, TSHR, TPO, Tg in AROshR cells were 2.82, 1.98, 2.65 and 2.31 times higher than those in AROshN cells, and the expressions in WROshR cells were 2.21, 1.78, 2.51 and 1.78 times higher than those in WROshN cells (t values: 13.80-21.93, all P<0.05). Conclusion Silence of REGγ can increase the gene expressions of the iodine uptake-related proteins and elevate the IUC of thyroid carcinoma cells. Key words: Thyroid neoplasms; Tumor cells, cultured; Proteasome endopeptidase complex; Gene silencing; Iodine radioisotopes

Analysis of clinical diagnosis and treatment of 20 children with hypophosphatemic rickets

Objective To analyze the clinical diagnosis and treatment data of 20 children with hypophosphatemic rickets (HR) in order to improve the clinical diagnosis and treatment of HR. Methods The retrospective analysis of clinical data of 20 cases with HR who were hospitalized at Children′s Hospital of Nanjing Medical University from May, 2010 to April, 2016 was performed to summarize the clinical characteristics.All patients were analyzed for the phosphate regulating gene with homologies to endopeptidase on the X chromosome(PHEX) gene by direct sequencing.If no mutations were detected, multiplex ligation-dependent probe amplification analysis was performed. Results All of the 20 cases with HR showed different degrees of growth retardation and typical X-ray rickets.After treatment, the clinical features were improved.Height standard deviation score (HSDS) was improved significantly with longer treatment time, and the difference was statistically significant(P=0.027). There was a correlation between the blood phosphorus fluctuation and secondary hyperparathyroidism(P<0.05). Nineteen cases had PHEX gene mutations.Truncating mutations was the most frequent mutation type, and 4 new mutations were found. Conclusions Clinical characte-ristics, laboratory test results and X-ray examination are important clinical index for the diagnosis of HR, and PHEX gene test can be used as an important auxiliary diagnostic tool.Early diagnosis and treatment can significantly improve the clinical manifestations of the patients. Key words: Hypophosphatemic rickets; Diagnosis; Treatment

Carboxylated multi-walled carbon nanotubes exacerbated oxidative damage in roots of Vicia faba L. seedlings under combined stress of lead and cadmium

Multi-walled carbon nanotubes (MWCNTs) and heavy metals could be absorbed and bioaccumulated by agricultural crops, implicating ecological risks. Herein, the present study investigated the ecotoxicological effects and mechanisms of individual carboxylated MWCNTs (MWCNTs-COOH) (2.5, 5.0 and 10 mg/L) and their combination with 20 µM Pb and 5 µM Cd (shortened as Pb + Cd) on roots of Vicia faba L. seedlings after 20 days of exposure. The results showed that the tested MWCNTs-COOH induced imbalance of nutrient elements, enhanced isozymes and activities of superoxide dismutase (SOD), guaiacol peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX), resulting in accumulation of carbonylated proteins, elevation of endoproteases (EPs) isozymes, and reduction of HSP70 synthesis in the roots. However, the tested MWCNTs-COOH facilitated the enrichment of Cd, Pb and Na elements, contributing to the decrease of SOD, CAT and APX activities, and the reduction of HSP70 synthesis, whereas the elevation of carbonylated proteins, EP activities and cell necrosis in the roots when Pb + Cd was combined in comparison to the treatments of MWCNTs-COOH, or Pb + Cd alone. Thus, the tested MWCNTs-COOH not only caused oxidative stress, but also aggravated the oxidative damage in the roots exposed to Pb + Cd in the culture solution.

Advances in Study of Properties, Recombinant Expression and Applications of Lysyl Endopeptidase

Advances in Study of Properties, Recombinant Expression and Applications of Lysyl Endopeptidase

The role of UCH-L3 and LC3II in the diagnosis of acute myeloid leukemia

Objective Todetect the mechanism of acute myeloid leukemia(AML) and the relationship between autophagy andubiquitin c-terminal hydrolases L3( UCH-L3) for providing new targets and guiding clinical management in AML. Methods 84 cases of AML patients and 25 controls were chosen from the First Affiliated Hospital of Dalian Medical University from 2014 to 2015, including 47 males and 37 females. The AML patients were divided into 3 groups : initialdiagnosis group[40 cases including 24 males and 16 females, with an median age of 54 (23-85)]; complete remission group[30 cases including 14 males and 16 females, with an median age of 45 (22-74)]and refractory group[14 cases including 9 males and 5 females, with an median age of 50 (18-80)]. Among those patients, there were 3 cases of M1, 42 cases of M2, 18 cases of M3, 3 cases of M4 and 18 cases of M5 subtypes.The expression of UCH-L3 and LC3II were detected by Real Time PCR and Western blot after the HL-60 cells were treated by TCID. The expression of UCH-L3 and LC3IIin the PBMC of AML patients and controls were detected with Real Time PCR. The expression levels of UCH-L3 and LC3II in different types of AML were analyzed. The relationship between the expression of LC3Ⅱand clinical features, clinical stages, laboratory results and therapeutic effects of patients were investigated. It further detected the expression of UCH-L3 and LC3IImRNA in post-induction status. t test were used for measurement data, χ2 test were performed for rate comparison; rank correlation test were performed for correlation analysis.Non-parametric test were performed for non-normal distribution data. Results Both the UCH-L3 and LC3 II were down-regulated after TCID treatment in HL-60 cellsat gene and protein levels (t=-29.435, t=-8.105, P<0.05). The expression of UCH-L3 in initial diagnosis group was lower than control group(Z=-3.87, P<0.05), butit was higher in remission group than initial diagnosis group and refractory group(Z=-6.70 , Z=-4.09, P<0.05). The expression level of LC3Ⅱin diagnosis group was significantly higher than control group, remission group and refractory group(Z=-6.96, Z=-5.32, Z=-3.52, P<0.05). Cytogenetic abnormalities in patients with high expression of LC3II were more common(χ2=6.510, P<0.05). The relative expression of UCH-L3 and LC3ⅡmRNA in the same patient before and after treatment were significantly different(P<0.05). During the remission, the expression of UCH-L3 was up-regulated compared with that before primary treatment, while the expression of LC3II was down-regulated. There was no statistically significant in the relative expression of UCH-L3 and LC3Ⅱamong the FAB type. Conclusion The UCH-L3 and autophagy are associated with pathogenesis of AML.(Chin J Lab Med, 2018, 41: 53-58) Key words: Leukemia, myeloid, acute; Cysteine endopeptidases; Microtubule-Associated Proteins; Autophagy

Correlations between chronic venous leg ulcer and matrix metalloproteinases

Chronic venous leg ulcer (CVLU) is a common and refractory complication of chronic venous diseases, and is clinically characterized by chronic leg ulcers and pain. Matrix metalloproteinases (MMPs) are a kind of highly conservative and zinc-dependent endopeptidases, and can be divided into 6 types according to their substrates and structures. Among the 6 types, collagenases, gelatinases and stromelysins play a key role in the occurrence and development of CVLU. Moreover, the up-regulation of MMP-1,-2,-3,-8 and ratio of MMP-2 to tissue inhibitor of metalloproteinase-2 (TIMP-2) is associated with delayed ulcer healing, whereas the up-regulation of MMP-7,-10,-13 and TIMP-1,-2 facilitates ulcer healing. However, roles of MMP-9 and -12 in venous ulcers are still unclear and need further study. According to functional characteristics of some MMPs, intervention of their composition and functions may provide new therapeutic targets for the treatment of CVLU. Key words: Varicose ulcer; Lower extremity; Matrix metalloproteinases; Extracellular matrix; Wound healing

Inhibitory Effect of Hizikia fusiformis Solvent-Partitioned Fractions on Invasion and MMP Activity of HT1080 Human Fibrosarcoma Cells.

Matrix metalloproteinases (MMPs) are endopeptidases that take significant roles in extracellular matrix degradation and therefore linked to several complications such as metastasis of cancer progression, oxidative stress, and hepatic fibrosis. Hizikia fusiformis, a brown algae, was reported to possess bioactivities, including but not limited to, antiviral, antimicrobial, and anti-inflammatory partly due to bioactive polysaccharide contents. In this study, the potential of H. fusiformis against cancer cell invasion was evaluated through the MMP inhibitory effect in HT1080 fibrosarcoma cells in vitro. H. fusiformis crude extract was fractionated with organic solvents, H2O, n-BuOH, 85% aqueous MeOH, and n-hexane (n-Hex). The non-toxicity of the fractions was confirmed by MTT assay. All fractions inhibited the enzymatic activities of MMP-2 and MMP-9 according to the gelatin zymography assay. Cell migration was also significantly inhibited by the n-Hex fraction. In addition, both gene and protein expressions of MMP-2 and -9, and tissue inhibitor of MMPs (TIMPs) were evaluated by reverse transcription-polymerase chain reaction and Western blotting, respectively. The fractions suppressed the mRNA and protein levels of MMP-2, MMP-9 while elevating the TIMP-1 and TIMP-2, with the H2O fraction being the least effective while n-Hex fraction the most. Collectively, the n-Hex fraction from brown algae H. fusiformis could be a potential inhibitor of MMPs, suggesting the presence of various derivatives of polysaccharides in high amounts.

Advances in bacterial extracellular metalloproteases and their pathogenic roles

Bacterial extracellular metalloproteases (BEMPs) are a large group of metal ion-containing proteases. All BEMPs identified so far are endopeptidase or endoprotease. BEMPs can be classified into nine metalloprotease families based on the sequences and structures of enzymatic molecules. Double-valence zinc ion (Zn2+ ) is necessarily required by catalytic centers of most BEMPs. The main function of BEMPs in non-pathogenic heterotrophic bacteria is to hydrolyze environmental proteins and polypeptides to provide various amino acids as nutrients. However, BEMPs of pathogenic bacteria, serving as important virulence factors, help the pathogens invade into hosts and spread in hosts. In recent years, the roles and mechanism of BEMPs in bacterial pathogenesis have attracted great attention. Here, we make a brief review about the structures and types as well as the functions and pathogenic roles of BEMPs. Key words: Bacteria; Metalloproteases; Structure; Function; Pathogenic role

Matrix metalloproteinases and skin diseases

Matrix metalloproteinases (MMPs) are a superfamily of zinc-dependent endopeptidases with highly homologous basic structure, and are mainly secreted by keratinocytes, fibroblasts, endotheliocytes, neutrophils and macrophages. Twenty-four members of MMPs have been found so far, and can be divided into 6 subgroups based on their substrates. MMPs are involved in several signaling pathways, and are closely related to cell differentiation, proliferation and inflammation. Further more, they play a vital role in the degradation of extracellular matrix, wound healing and tissue reconstruction, and participate in multiple pathogenic mechanisms of various skin diseases and in wound healing process. To update knowledge about MMPs in relevant skin diseases may facilitate further exploration into the pathogenesis of these skin diseases, and even provide new therapeutic targets. Key words: Skin diseases; Therapeutic uses; Cicatrix; Ulcer; Matrix metalloproteinases; Signaling pathway

Changing the treatment of heart failure with reduced ejection fraction: clinical use of sacubitril-valsartan combination.

Despite significant therapeutic advances, patients with chronic heart failure (HF) remain at high risk of morbidity and mortality. Sacubitril valsartan (previously known as LCZ696) is a new oral agent approved for the treatment of symptomatic chronic heart failure in adults with reduced ejection fraction. It is described as the first in class angiotensin receptor neprilysin inhibitor (ARNI) since it incorporates the neprilysin inhibitor, sacubitril and the angiotensin II receptor antagonist, valsartan. Neprilysin is an endopeptidase that breaks down several vasoactive peptides including natriuretic peptides (NPs), bradykinin, endothelin and angiotensin II (Ang-II). Therefore, a natural consequence of its inhibition is an increase of plasmatic levels of both, NPs and Ang-II (with opposite biological actions). So, a combined inhibition of these both systems (Sacubitril / valsartan) may enhance the benefits of NPs effects in HF (natriuresis, diuresis, etc) while Ang-II receptor is inhibited (reducing vasoconstriction and aldosterone release). In a large clinical trial (PARADIGM-HF with 8442 patients), this new agent was found to significantly reduce cardiovascular and all cause mortality as well as hospitalizations due to HF (compared to enalapril). This manuscript reviews clinical evidence for sacubitril valsartan, dosing and cautions, future directions and its considered place in the therapy of HF with reduced ejection fraction.