Electrospun Propolis-coated PLGA Scaffold Enhances the Osteoinduction of Mesenchymal Stem Cells

BACKGROUND

Major injuries that are caused by trauma and cancer can not be repaired through bone remodeling. The goal of bone regeneration by tissue engineering approaches is to fabricate bone implants in order to restore bone structure and functions. The use of stem cells and polymer scaffolds provides the conditions for tissue regeneration based on tissue engineering.

OBJECTIVE

This study aimed to fabricate a combined matrix of poly(lactide-co-glycolide) (PLGA) and propolis extract, which is a mixture of pollen and beeswax collected by bees from certain plants and has long been used in traditional herbal medicine, to promote the osteogenic differentiation of human adipose- derived mesenchymal stem cells (AD-MSCs).

METHODS

The scaffold was fabricated through electrospinning and was immersed in a propolis extract solution. Then, AD-MSCs were cultured and differentiated into the osteogenic lineage. The cell viability on the scaffold was evaluated by MTT assay. Osteogenic differentiation of the seeded stem cells was detected by evaluating calcium content, alkaline phosphatase (ALP) activity, and the expression of bonespecific genes.

RESULTS

The viability of cells was not affected by propolis-coated and uncoated fabricated scaffolds, while higher calcium content, ALP activity, and expression of RUNX-2, type I collagen, osteocalcin, and osteonectin were observed in cells differentiated on propolis-coated PLGA scaffold on days 7, 14, and 21 of differentiation compared to PLGA scaffold.

CONCLUSION

The results of this study showed that the presence of propolis in the scaffold could lead to better cell attachment and strengthen the osteoinduction process in stem cells.

Evaluation of an antibacterial peptide-loaded amniotic membrane/silk fibroin electrospun nanofiber in wound healing

Antimicrobial peptides (AMPs) are among the compounds that have significant potential to deal with infectious skin wounds. Using wound dressings or skin scaffolds containing AMPs can be an effective way to overcome infections caused by antibiotic-resistant strains. In this study, we developed an amniotic membrane-based skin scaffold using silk fibroin to improve mechanical properties and CM11 peptide as an antimicrobial peptide. The peptide was coated on the scaffold using the soaking method. The fabricated scaffold was characterised by SEM and FTIR, and their mechanical strength, biodegradation, peptide release, and cell cytotoxicity analyses were performed. Then, their antimicrobial activity was measured against antibiotic-resistant strains of Pseudomonas aeruginosa and Staphylococcus aureus. The in vivo biocompatibility of this scaffold was evaluated by subcutaneously implanting it under the skin of the mouse and counting lymphocytes and macrophages in the implanted area. Finally, the regenerative ability of the scaffold was analyzed in the mouse full-thickness wound model by measuring the wound diameter, H&E staining, and examining the expression rate of genes involved in the wound healing process. The developed scaffolds exerted an inhibiting effect on the bacteria growth, indicating their proper antimicrobial property. In vivo biocompatibility results showed no significant count of macrophages and lymphocytes between the test and control groups. The wound closure rate was significantly higher in the wound covered with fibroin electrospun-amniotic membrane loaded with 32 μg/mL CM11, where the relative expression rates of collagen I, collagen III, TGF-β1 and TGF-β3 were higher compared with the other groups.

Host and Pathogen-Directed Therapies against Microbial Infections Using Exosome- and Antimicrobial Peptide-derived Stem Cells with a Special look at Pulmonary Infections and Sepsis

Microbial diseases are a great threat to global health and cause considerable mortality and extensive economic losses each year. The medications for treating this group of diseases (antibiotics, antiviral, antifungal drugs, etc.) directly attack the pathogenic agents by recognizing the target molecules. However, it is necessary to note that excessive use of any of these drugs can lead to an increase in microbial resistance and infectious diseases. New therapeutic methods have been studied recently using emerging drugs such as mesenchymal stem cell-derived exosomes (MSC-Exos) and antimicrobial peptides (AMPs), which act based on two completely different strategies against pathogens including Host-Directed Therapy (HDT) and Pathogen-Directed Therapy (PDT), respectively. In the PDT approach, AMPs interact directly with pathogens to interrupt their intrusion, survival, and proliferation. These drugs interact directly with the cell membrane or intracellular components of pathogens and cause the death of pathogens or inhibit their replication. The mechanism of action of MSC-Exos in HDT is based on immunomodulation and regulation, promotion of tissue regeneration, and reduced host toxicity. This review studies the potential of mesenchymal stem cell-derived exosomes/ATPs therapeutic properties against microbial infectious diseases especially pulmonary infections and sepsis.

An inspired microenvironment of cell replicas to induce stem cells into keratocyte-like dendritic cells for corneal regeneration

Corneal stromal disorders due to the loss of keratocytes can affect visual impairment and blindness. Corneal cell therapy is a promising therapeutic strategy for healing corneal tissue or even enhancing corneal function upon advanced disorders, however, the sources of corneal keratocytes are limited for clinical applications. Here, the capacity of cell-imprinted substrates fabricated by molding human keratocyte templates to induce differentiation of human adipose-derived stem cells (hADSCs) into keratocytes, is presented. Keratocytes are isolated from human corneal stroma and grown to transmit their ECM architecture and cell-like topographies to a PDMS substrate. The hADSCs are then seeded on cell-imprinted substrates and their differentiation to keratocytes in DMEM/F12 (with and without chemical factors) are evaluated by real-time PCR and immunocytochemistry. The mesenchymal stem cells grown on patterned substrates present gene and protein expression profiles similar to corneal keratocytes. In contrast, a negligible expression of myofibroblast marker in the hADSCs cultivated on the imprinted substrates, is observed. Microscopic analysis reveals dendritic morphology and ellipsoid nuclei similar to primary keratocytes. Overall, it is demonstrated that biomimetic imprinted substrates would be a sufficient driver to solely direct the stem cell fate toward target cells which is a significant achievement toward corneal regeneration.

Targeted delivery of a short antimicrobial peptide (CM11) against Helicobacter pylori gastric infection using concanavalin A-coated chitosan nanoparticles

Helicobacter pylori is the cause of most cases of stomach ulcers and also causes some digestive cancers. The emergence and spread of antibiotic-resistant strains of H. pylori is one of the most important challenges in the treatment of its infections. The present study aims to develop a concanavalin A (ConA) coated chitosan (CS) nanocarrier-based drug delivery for the targeted release of peptides to the site of H. pylori infection. Accordingly, chitosan was used as an encapsulating agent for CM11 peptide delivery by applying ionotropic gelation method. Con-A was used for coating CS nanoparticles to target H. pylori. The CS NPs and ConA-CS NPs were characterized by FTIR, dynamic light scattering (DLS), and scanning electron microscopy (SEM). The MIC of CM11-loaded ConA-CS NPs against H. pylori SS1 strain was analyzed in vitro. In order to evaluate the treatment efficiency in vivo, a gastric infection model of H. pylori SS1 strain was established in mice and histopathological studies and IL-1β cytokine assay were performed. Based on the results, the size frequency for CS NPs and ConA-CS NPs was about 200 and 350 nm, respectively. The prepared CM11-loaded ConA-CS NPs exhibited antibacterial activity against H. pylori SS1 strain with a concentration of 32 µg/ml. The highest healing process was observed in synthesized CM11-loaded ConA-CS NPs treatments and a significant decrease in IL-1β was observed. Our findings highlight the potential of chitosan nanoparticles as a drug delivery vehicle in the treatment of gastric infection model of H. pylori SS1 strain.

Neuroprotective activity of green synthesized silver nanoparticles against methamphetamine-induced cell death in human neuroblastoma SH-SY5Y cells

The present study aimed to investigate the neuroprotective activity of the black peel pomegranate extract, and silver nanoparticles (AgNPs) biosynthesized using the extract. We pretreated the human neuroblastoma SH-SY5 cells with the extract and AgNPs and evaluated the neuroprotective activity of these agents against methamphetamine (Meth) cytotoxicity. The NPs were spherical with 19 ± 8 nm size, - 28 mV surface charge, and 0.20 PDI. Meth killed the cells by increasing proapoptotic (Bax, PTEN, AKT, PI3K, NF-κB, P53, TNF-α, Cyt C, and Cas 3) and decreasing the antiapoptotic genes (Bcl-2) expression. Exposure to Meth caused DNA fragmentation and increased the intercellular ROS and malondialdehyde (MDA) levels while reducing the mitochondrial membrane potential (MMP). A 4-h pretreatment of the cells with the extract and AgNPs could retain the viability of the cells above 80% by increasing the Bcl-2 expression up to fourfold and inhibiting the cell death pathways. ROS, MDA, and MMP levels in the pretreated cells were close to the control group. The percentage of necrosis in cells pretreated with the extract and AgNPs declined to 32% and 8%, respectively. Our promising findings indicated that AgNPs could reduce Meth-induced oxidative stress and prevent necrotic and apoptotic cell death by regulating related genes' expression.

A Short Cationic Peptide Derived From Cecropin And Melittin Peptides Induce Apoptosis In Jurkat And Raji Leukemia Cell Lines

BACKGROUND

The creation of brand-new, potent, and less harmful medications to treat leukemia is urgently needed. Antimicrobial peptides (AMPs) have drawn a lot of interest as potential substitutes for chemotherapy. In the present investigation, the anticancer activity of CM11, a short cationic AMP, was assessed on Jurkat and Raji leukemia cell lines and peripheral blood mononuclear cells (PBMCs).

METHODS

Different CM11 doses were applied to the Jurkat and Raji cell lines and PBMCs throughout a 24-hour period. The impact of the CM11 on cell viability and toxicity was assessed using an MTT assay. Flow cytometry and Real-Time PCR were used to analyze the effect of this peptide on apoptotic/ necrosis pathways and assess the ratio expression of the P53 and Bcl-2 genes, respectively.

RESULT

Despite the fact that peptide toxicity was successful in a variety of cell lines, cancer cells were more sensitive to the medication. The survival of Jurkat and Raji cell lines treated with 32 µg/ml peptide was 47% and 51%, respectively, while the survival of normal PBMC cells was about 65%. According to flow cytometry, Jurkat and Raji cells exposed to peptide had much greater levels of apoptosis than PBMCs. Peptide-treated cells were associated with increased expression of P53 the gene and decreased expression of the Bcl-2 gene.

CONCLUSION

These results revealed that the CM11 caused more cytotoxicity to leukemia Raji and Jurkat leukemia cells compared to the normal cells by apoptosis pathway. Our findings demonstrated the potential of CM11 peptide to develop as a new antileukemic agent.

A CONCISE REVIEW ON THE ANTIMICROBIAL PEPTIDES AND THEIR CRITICAL ACTIVITY AGAINST INTRACELLULAR TARGETS OF BACTERIA

Multi-drug resistance, which is the consequence of overusing antibiotics, has been shown to become a common problem in the medical environments. Accordingly, finding a substitute for daily used antibiotics is a topic of interest in medical microbiology and biotechnology. Antimicrobial peptides (AMPs) are among the main candidates for controlling this problem. These peptides are regarded as the critical defensive line in many organisms. These AMPs act as an innate immunity against pathogenic microorganisms; such as bacteria or fungi. AMPs could destroy their target via different methods; including membrane pore-formation or by targeting their intracellular targets and disrupting the normal cellular activity. Some AMPs have the property of targeting constructs like DNA, RNA, protein synthesis and folding and inhibiting cell life activities; such as normal metabolism or cell division. At this study, we reviewed more than 130 papers that were concerning the importance of intracellular targeting AMPs, by searching the valuable data sources such as PubMed, Scopus, and Web of Science. These AMPs can be considered as one of the possible options to improve the treatment of infected patients. In this review, it was aimed to discuss the activity of intracellular AMPs and provide an outlook for future studies.

The Antifungal and Antibacterial Effect of Citrullus Colocynthis: In Vitro Study

Introduction: Bacteria almost exclusively cause caries and other oral and dental diseases. This study evaluated the inhibitory effect of the alcoholic extract of Citrullus colocynthis on bacteria and fungi common in oral bacteria diseases. Method and materials: The ethanol extract and essential oil of Citrullus colocynthis were obtained via water distillation. After conducting phytochemical tests, including determination of total phenolic and flavonoid compounds of the extracts, GC-MASS test and microbial tests of the extracts were conducted on S. mutans, E. coli, S. salivarius, L. acidophilus, C. albicans, and S. aureus. The cytotoxicity test was assessed by MTT assay. Results: MIC and MBC values for S. mutans, S. salivalius, and L. acidophilus were 1.56 mg/ml and 3.12 mg/ml, respectively. Moreover, Citrullus colocynthis also has an inhibitory effect on bacteria and C. albicans at these concentrations, according to the DAD test. The survival rate of cells at concentrations of 5 mg/ml and 10 mg/ml was less than 50%, and at concentrations of 2.5 mg/ml and 1.25 mg/ml was less than 70% after 24 hours and 48 hours. Conclusion: According to the cytotoxicity results of this plant at concentrations of 1.56 mg/ml and 3.125 mg/ml, the ethanolic extract of C. colocynthis has inhibitory and lethal effects against pathogenic bacteria and fungi.

Strontium doped bioglass incorporated hydrogel-based scaffold for amplified bone tissue regeneration

Repairing of large bone injuries is an important problem in bone regeneration field. Thus, developing new therapeutic approaches such as tissue engineering using 3D scaffolds is necessary. Incorporation of some bioactive materials and trace elements can improve scaffold properties. We made chitosan/alginate/strontium-doped bioglass composite scaffolds with optimized properties for bone tissue engineering. Bioglass (BG) and Sr-doped bioglasses (Sr-BG) were synthesized using Sol–Gel method. Alginate-Chitosan (Alg/Cs) scaffold and scaffolds containing different ratio (10%, 20% and 30%) of BG (Alg/Cs/BG10, 20, 30) or Sr-BG (Alg/Cs/Sr-BG10, 20, 30) were fabricated using freeze drying method. Characterization of bioglasses/scaffolds was done using zeta sizer, FTIR, XRD, (FE) SEM and EDS. Also, mechanical strength, antibacterial effect degradation and swelling profile of scaffolds were evaluated. Bone differentiation efficiency and viability of MSCs on scaffolds were determined by Alizarin Red, ALP and MTT methods. Cell toxicity and antibacterial effect of bioglasses were determined using MTT, MIC and MBC methods. Incorporation of BG into Alg/Cs scaffolds amplified biomineralization and mechanical properties along with improved swelling ratio, degradation profile and cell differentiation. Mechanical strength and cell differentiation efficiency of Alg/Cs/BG20 scaffold was considerably higher than scaffolds with lower or higher BG concentrations. Alg/Cs/Sr-BG scaffolds had higher mechanical stability and more differentiation efficiency in comparison with Alg/Cs and Alg/Cs/BG scaffolds. Also, Mechanical strength and cell differentiation efficiency of Alg/Cs/Sr-BG20 scaffold was considerably higher than scaffolds with various Sr-BG concentrations. Biomineralization of Alg/Cs/BG scaffolds slightly was higher than Alg/Cs/Sr-BG scaffolds. Overall, we concluded that Alg/Cs/Sr-BG20 scaffolds are more suitable for repairing bone major injuries.

Evaluation of antimicrobial and cytotoxic effects of Echinacea and Arctium extracts and Zataria essential oil

Dental caries and oral infections have become a widespread issue in the modern world. This study aimed to investigate the antibacterial, antifungal, and cytotoxicity characteristics of the extracts of Echinacea purpura, Arctium lappa, and the essential oil of Zataria multiflora as a potential herbal mouthwash. The essential oil of Z. multiflora leaves and the extracts of E. purpurea and A. lappa roots were prepared. The characterization was carried out by GC-MS and also, total phenol and flavonoid were assed for all three samples. The antimicrobial and anti-biofilm effects were evaluated against Streptococcus mutans, Streptococcus mitis, Streptococcus salivarius, Lactobacillus acidophilus, Escherichia coli, Staphylococcus aureus, and Candida albicans. The cytotoxic effect of the samples was evaluated on HEK 293 and HDFa cells by MTT test. Thymol and carvacrol contents in EO of Z. multiflora were measured at 31% and 42.2%, respectively. A. lappa had the lowest total phenolic and flavonoid value among the samples. On the other hand, the total phenolic content of Z. multiflora and the total flavonoid content of E. purpurea were the highest. The MIC values of Zataria, Arctium, and Echinacea against S. mutans were 0.011% v/v, 187.5 mg/ml, and 93.75 mg/ml, while MBC were 0.011% v/v, 375 mg/ml, and 187.5 mg/ml, respectively. The formulation showed bactericidal activity against S. mutans in the concentration of 5.86 mg/ml for Echinacea and Burdock extracts and 0.08 µl/ml for EO of Zataria. The formulation significantly affected microbial biofilm formation and induced biofilm degradation. The cell viability percentages were higher than 50% during 24 and 48 h. The formulation had a significant antimicrobial effect on cariogenic bacteria and C. albicans, with the lowest cytotoxic effects. Therefore, this formulation can be an appropriate candidate for mouthwash.

Emerging tissue engineering strategies for the corneal regeneration

Cornea as the outermost layer of the eye is at risk of various genetic and environmental diseases that can damage the cornea and impair vision. Corneal transplantation is among the most applicable surgical procedures for repairing the defected tissue. However, the scarcity of healthy tissue donations as well as transplantation failure has remained as the biggest challenges in confront of corneal grafting. Therefore, alternative approaches based on stem-cell transplantation and classic regenerative medicine have been developed for corneal regeneration. In this review, the application and limitation of the recently-used advanced approaches for regeneration of cornea are discussed. Additionally, other emerging powerful techniques such as 5D printing as a new branch of scaffold-based technologies for construction of tissues other than the cornea are highlighted and suggested as alternatives for corneal reconstruction. The introduced novel techniques may have great potential for clinical applications in corneal repair including disease modeling, 3D pattern scheming, and personalized medicine.

Osteogenesis Improvement of Gelatin-Based Nanocomposite Scaffold by Loading Zoledronic Acid

Bisphosphonates (BPs) such as Zoledronic acid (ZA) are a subset of synthetic small molecules, which are now marketed as the main drugs to stimulate the growth and differentiation of osteoblast cells, thereby increasing bone formation as well as preventing bone loss. Also, Halloysite Nanotubes (HNTs)-polymer composites have attracted a lot of attention due to their high surface-to-volume ratio, low density, and high hydrophilicity, and are easily dispersed in hydrophilic biopolymers. In addition, their ability to carry enough amounts of drugs and the ability to control release has been demonstrated. Based on studies, the Gelatin-based scaffold with Halloysite nanotube (HNT) has the capacity as a drug carrier and Zoledronic acid (ZA) sustains release. Previous studies show that using ZA intravenously has some severe side effects and limitations. But by attention to the advantages of its osteogenesis, the current study has been done in order to reduce the side effects of local delivery of it. The 3-dimensional scaffolds were prepared by the Freeze-drying method. Characterization methods such as FE-SEM, FTIR, XRD, and release behavior of the scaffold has been performed to evaluate the features of the scaffolds. In fact, as-prepared Gel-HNT/ZA release 49% ZA in Phosphate Buffered Saline (PBS) within 21 days. The mechanical properties have been increased after adding HNTs and ZA from 10.27 to 26.18 MPa. Also, the water absorption has been increased after adding HNTs and ZA from 1.67 to 5.02 (g/g). Seeded human Adipose stem cells (hASCs) on the prepared scaffolds showed that the ZA effectively elevated the proliferation of the hASCs and also the MTT results proved the non-toxicity of all prepared scaffolds by high cell viability (˃80%). The osteogenic differentiation has been accelerated as displayed by ALP and Ca assay. The results propose that the HNTs-loaded Gelatin scaffold could control the releasing of ZA and its localized delivery at the defect site, simultaneously promoting the mechanical and osteogenesis ability of gelatin-based scaffolds.

A contemporary review on the important role of in silico approaches for managing different aspects of COVID-19 crisis

In the last century, the emergence of in silico tools has improved the quality of healthcare studies by providing high quality predictions. In the case of COVID-19, these tools have been advantageous for bioinformatics analysis of SARS-CoV-2 structures, studying potential drugs and introducing drug targets, investigating the efficacy of potential natural product components at suppressing COVID-19 infection, designing peptide-mimetic and optimizing their structure to provide a better clinical outcome, and repurposing of the previously known therapeutics. These methods have also helped medical biotechnologists to design various vaccines; such as multi-epitope vaccines using reverse vaccinology and immunoinformatics methods, among which some of them have showed promising results through in vitro, in vivo and clinical trial studies. Moreover, emergence of artificial intelligence and machine learning algorithms have helped to classify the previously known data and use them to provide precise predictions and make plan for future of the pandemic condition. At this contemporary review, by collecting related information from the collected literature on valuable data sources; such as PubMed, Scopus, and Web of Science, we tried to provide a brief outlook regarding the importance of in silico tools in managing different aspects of COVID-19 pandemic infection and how these methods have been helpful to biomedical researchers.

Lipid-Based Nanoparticles for Targeted Delivery of the Anti-Cancer Drugs: A Review

Abstract:

Cancer is one of the main reasons for mortality worldwide. Chemotherapeutic agents have been effectively designed to increase certain patients' survival rates, but ordinarily designed chemotherapeutic agents necessarily deliver toxic chemotherapeutic drugs to healthy tissues, resulting in serious side effects. Cancer cells can often acquire drug resistance after repeated dosing of current chemotherapeutic agents, restricting their efficacy. Given such obstacles, investigators have attempted to distribute chemotherapeutic agents using targeted drug delivery systems (DDSs), especially nanotechnology-based DDSs. Lipid-Based Nanoparticles (LBNPs) are a large and complex class of substances that have been utilized to manage a variety of diseases, mostly cancer. Liposomes seem to be the most frequently employed LBNPs, owing to their high biocompatibility, bioactivity, stability, and flexibility; howbeit Solid Lipid Nanoparticles (SLNs) and Non-structured Lipid Carriers (NLCs) have lately received a lot of interest. Besides that, there are several reports that concentrate on novel therapies via LBNPs to manage various forms of cancer. In the present research, the latest improvements in the application of LBNPs have been shown to deliver different therapeutic agents to cancerous cells and have been demonstrated LBNPs also can be a quite successful candidate in cancer therapy for subsequent use.

The antimicrobial effect of quorum sensing autoinducers of Pseudomonas aeruginosa, C12-HSL and C4-HSL, against MDR Staphylococcus aureus isolates

In the current study, we investigated the antibacterial activity of main quorum sensing autoinducers of Pseudomonas aeruginosa, C12-HSL and C4-HSL, against MDR Staphylococcus aureus isolates and their synergistic effects with some common antibiotics. Forty clinical isolates of S. aureus were collected and their antibiotic susceptibility pattern was evaluated. Then, 10 resistant isolates were selected for further studies. In the following, the antibacterial activity of quorum sensing C12-HSL and C4-HSL inducers of P. aeruginosa was evaluated against selected isolates based on the microdilution method and Time Killing assay as well as their synergistic activity with selected antibiotics. The ability of inductors to hemolysis and their cytotoxicity on CHO and HeLa cell lines was also assessed. For the assessment of antibacterial activity, Acinetobacter baumannii was used as negative control. The results demonstrated that C12 and C4 have antibacterial activity against MDR S. aureus isolates but had no effect on A. baumannii. Time Killing test showed that at 2X MIC concentration, the maximum inhibition (100%) is observed after 120 min for C12 and 240 min for C4. The IC₅₀ of inducers was about 512 μg/ml. In addition, no synergistic effects were observed.

In Silico Analysis of Inhibiting Papain-like Protease from SARS-CoV-2 by Using Plant-Derived Peptides

SARS-CoV-2 is a corona virus that has been the cause for one of the deadliest pandemics of history, started since 2019. Suppressing the activity of the critical enzymes in the SARS-CoV-2 could potentially inhibit a vital step in viral life cycle. Papain-like protease (PLpro) could be regarded as a critical enzyme in viral replication of SARS-CoV-2. In this research, it was aimed to suppress the activity of PLpro enzyme by using potential plant-derived protease inhibitor peptides. For this purpose, 11 plant derived peptides that could potentially inhibit protease activity were selected from literature. The structures of the PLpro and the peptide ligands were acquired from PDB (protein data bank) and after structural optimization, were docked by using HADDOCK 2.4 program. Analyzing the results indicated that VcTI from Veronica hederifolia provides effective molecular interactions at both liable Zn site and classic active site of PLpro, making it a potential inhibitory ligand for this enzyme that could be used for halting the replication of SARS-CoV-2. Molecular dynamic assay confirmed that the selected receptor and ligand complex was stable. Future in vitro and in vivo investigations are required to verify the efficiency of this compound as a potential therapeutic against SARS-CoV-2 infection.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s10989-021-10331-8.

Supplementation of zebrafish (Danio rerio) diet using a short antimicrobial peptide: Evaluation of growth performance, immunomodulatory function, antioxidant activity, and disease resistance

Short-chain bioactive peptides are new and promising antimicrobial, immune moderating, and antioxidant agents. Therefore, the present study was conducted to evaluate in vitro antibacterial activity of CM11, a short antimicrobial peptide (AMP), against Streptococcus iniae and Yersinia ruckeri as fish pathogenic bacteria using standard disk diffusion and microdilution assays. In addition, in vivo effects of CM11 on fish growth, immunity, antioxidant activity, and disease resistance were evaluated using zebrafish (Danio rerio) as an animal model. For in vivo study, based on in vitro susceptibility results, four diets were designed to include zero (as control), 10, 20, and 50 μg of CM11 per g diet referred to as control, P1, P2, and P3 treatments, respectively. After eight weeks of dietary trial, fish were challenged with Streptococcus iniae, and the survival rate was calculated for a period of two weeks. Results showed that CM11 effectively inhibited the growth of S. iniae and Y. ruckeri on agar plates at a concentration of eight μg/ml. Minimum inhibitory and minimum bactericidal concentrations of CM11 were measured at 8 and 32 μg/ml for S. iniae and 16 and 64 μg/ml Y. ruckeri, respectively. In vivo results showed no noticeable effects on fish growth parameters, however, feed conversion ratio (FCR) was found lower in P3 and P2 compared to control (P < 0.05). Immunological and antioxidant responses were found strongly affected by CM11 in all treatment groups in which the highest values were found in the P3 treated group. Key immune and antioxidant genes were up-regulated particularly in fish receiving the highest level of CM11 (P3). Fish receiving the CM11 peptide showed better survival when challenged with S. iniae. These findings suggest the potential of CM11 for use in aquaculture as an antibacterial and immunostimulant agent.

Fabrication and characterization of an antibacterial chitosan/silk fibroin electrospun nanofiber loaded with a cationic peptide for wound-dressing application

Wound infections are still problematic in many cases and demand new alternatives for current treatment strategies. In recent years, biomaterials-based wound dressings have received much attention due to their potentials and many studies have been performed based on them. Accordingly, in this study, we fabricated and optimized an antibacterial chitosan/silk fibroin (CS/SF) electrospun nanofiber bilayer containing different concentrations of a cationic antimicrobial peptide (AMP) for wound dressing applications. The fabricated CS/SF nanofiber was fully characterized and compared to the electrospun silk fibroin and electrospun chitosan alone in vitro. Then, the release rate of different concentrations of peptide (16, 32, and 64 µg/ml) from peptide-loaded CS/SF nanofiber was investigated. Finally, based on cytotoxic activity, the antibacterial activity of scaffolds containing 16 and 32 µg/ml of the peptide was evaluated against standard and multi-drug resistant strains of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa isolated from burn patients. The peptide-loaded CS/SF nanofiber displayed appropriate mechanical properties, high water uptake, suitable biodegradation rate, a controlled release without cytotoxicity on Hu02 human foreskin fibroblast cells at the 16 and 32 µg/ml concentrations of peptide. The optimized CS/SF containing 32 μg/ml peptide showed strong antibacterial activity against all experimental strains from standard to resistance. The results showed that the fabricated antimicrobial nanofiber has the potential to be applied as a wound dressing for infected wound healing, although further studies are needed in vivo.

Response to Mechanical Cues by Interplay of YAP/TAZ Transcription Factors and Key Mechanical Checkpoints of the Cell: A Comprehensive Review

Many factors including growth factors (GF), scaffold materials, and chemical and physical cues determine the cell behaviors. For many years, growth factors have been considered as the pivotal cell behavior regulators, whereas recent studies emphasize also the key role of physical factors such as mechanical forces, cell shape, surface topographies, and extracellular matrix (ECM) in regulating the cell proliferation, apoptosis, differentiation, etc. through mechanotransduction pathways. In this process, the cell morphology and mechanical properties of the cell's micro/ nano-environments and ECM can be conveyed to the nucleus by regulating transcriptional factors such as Yes-associated protein and transcriptional coactivator with PDZ-binding motif (TAZ). Generally, YAP/TAZ activity is considered as the key factor for the growth of whole organs, however, recent studies have also repeatedly addressed the role of YAP/TAZ in mechanotransduction. In this review, the biological functions of the YAP/TAZ pathway and its contribution to the mechanotransduction and cell behavior regulation in response to the mechanical cues have been summarized. Also, the role of key mechanical checkpoints in the cell including focal adhesions, cytoskeletal tension, Rho small GTPases, and nuclear membrane protein elements involved in the transfer of environmental mechanical cues from the cell surface to the nucleus and their effect in regulating the YAP/TAZ activity are discussed.

Antiviral peptides against Coronaviridae family: A review

The Coronaviridae family comprises large enveloped single-stranded RNA viruses. The known human-infecting coronaviruses; severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East respiratory syndrome coronavirus (MERS-CoV), novel SARS-CoV-2, human coronavirus (HCoV)-NL63, HCoV-229E, HCoV-OC43 and HKU1 cause mild to severe respiratory infections. The viral diseases induced by mammalian and avian viruses from Coronaviridae family pose significant economic and public health burdens. Due to increasing reports of viral resistance, co-infections and the emergence of viral epidemics such as COVID-19, available antiviral drugs show low or no efficacy, and the production of new treatments or vaccines are also challenging. Therefore, demand for the development of novel antivirals has considerably increased. In recent years, antiviral peptides have generated increasing interest as they are from natural and computational sources, are highly specific and effective, and possess the broad-spectrum activity with minimum side effects. Here, we have made an effort to compile and review the antiviral peptides with activity against Coronaviridae family viruses. They were divided into different categories according to their action mechanisms, including binding/attachment inhibitors, fusion and entry inhibitors, viral enzyme inhibitors, replication inhibitors and the peptides with direct and indirect effects on the viruses. Reported studies suggest optimism with regard to the design and production of therapeutically promising antiviral drugs. This review aims to summarize data relating to antiviral peptides particularly with respect to their applicability for development as novel treatments.

Protective Effect of Vitamin D3 Against Pb-Induced Neurotoxicity by Regulating the Nrf2 and NF-κB Pathways

Lead (Pb) is a known toxic heavy metal which accumulates in different tissues and causes oxidative stress (OS) and inflammation. The brain tissue is considered as one of the most vulnerable organs to the Pb-induced toxicity. The aim of this study was to investigate the therapeutic effects of vitamin D3 (VD) supplementation against the damages caused by chronic Pb toxicity in the cerebral cortex. Forty Wistar rats were divided into four equal groups and were treated as follows: control group received no treatment, VD group received 1000 IU/kg of VD by intramuscular injection every other day, Pb group received 1000 mg/L of Pb in drinking water, and Pb + VD group received VD and Pb simultaneously. The experiment lasted for 4 weeks and the analyses were conducted 24 h after the last administrations. The obtained results demonstrated that Pb significantly increased cortical lipid peroxidation and reactive oxygen species (ROS) levels. At the same time, there was a significant reduction in glutathione (GSH) content, catalase (CAT), and superoxide dismutase (SOD) activities, as well as a significant increase in the tissue level of inflammatory cytokines. Furthermore, Pb increased the messenger RNA (mRNA) expression level of nuclear factor erythroid 2-related factor 2 (Nrf2) and nuclear factor-kappa B (NF-κB). Anyhow, VD administration during the period of Pb exposure suppressed the OS and inflammation by increasing the antioxidant molecules and decreasing the inflammatory cytokines and consequently repaired Pb-induced cortical tissue damages. Remarkably, these responses were concomitant with the alterations in Nrf2 and NF-κB gene expressions. In conclusion, the present study discloses the potential protective effects for VD against Pb-induced neurotoxicity via anti-inflammatory and antioxidative mechanisms.

Molecular and serological detection and of Toxoplasma gondii in small ruminants of southwest Iran and the potential risks for consumers

Toxoplasmosis is one of the most important zoonotic diseases with serious health risks for humans, especially for immunodeficient patients, and can lead to abortion in pregnant women worldwide. The oral uptake of sporulated oocysts and/or consumption of undercooked/raw meat of animals infected with Toxoplasma gondii can infect other animals and humans. Heart, liver, and meat tissues of 150 sheep and 150 goats from a slaughterhouse in Ahvaz, Iran, were collected during autumn 2018 and analyzed via polymerase chain reaction (PCR) to detect parasitic DNA in the animal tissues. Moreover, antibodies against T. gondii of 150 sera samples were detected as the targets by in-house enzyme-linked immunosorbent assay (in-house ELISA). A total of 26 (17.3%), 33 (22%), and 48 (32%) of liver, meat, and heart samples in sheep, and a total of 24 (16%), 26 (17.3%), and 36 (24%) of liver, meat, and heart samples in goats, respectively, showed positive PCR results. Besides, the ELISA evaluation of sera samples from 150 sheep and 150 goats resulted in 26 (13.3%) and 16 (10.6%) positive cases, respectively. A significant difference was also found between PCR-positive heart samples and ELISA-positive sera samples of both animal species (p < 0.05), but no significant difference existed between PCR-positive liver samples and ELISA-positive sera samples of both species (p > 0.05). The results of this study confirm the presence of T. gondii in sheep and goats’ consumable organs, highlighting the need to avoid consuming raw or uncooked organs of these animal species to prevent human infection with T. gondii.

Development of physical, mechanical, antibacterial and cell growth properties of poly(glycerol sebacate urethane) (PGSU) with helping of curcumin and hydroxyapatite nanoparticles

Biocompatible and antimicrobial elastomers with controlled hydrophilicity and degradation rate, as well as appropriate stiffness and elasticity, are interesting for biomedical applications, such as regenerative medicine and tissue engineering.

Conjugation of imipenem to silver nanoparticles for enhancement of its antibacterial activity against multi-drugresistant isolates of Pseudomonas aeruginosa

Due to the broad-spectrum of antibiotic resistance, herein we investigated the possibility of using imipenemconjugated silver nanoparticles (IMP-AgNPs) against multidrug-resistant isolates of Pseudomonas aeruginosa. For this purpose, 200 clinical isolates were tested against different antibiotics to determine the antimicrobial susceptibility. To identify blaVIM and blaIMP resistance genes, PCR was used. The synthesized AgNPs and conjugants were characterized using UV-vis spectroscopy, XRD, SEM, TEM, DLS, and FTIR. The stability, drug release kinetics, cytotoxicity, hemolytic and apoptotic effects of NPs were also investigated. MIC of the imipenem, AgNPs, and conjugants were evaluated versus P. aeruginosa isolates. Finally, the effects of the IMP-AgNPs to heal burn wounds in rats was evaluated. According to the results, about 68% of isolates showed resistance to imipenem (MIC ≥ 64 μg/ml to ≥ 512 μg/ml). Analytical results verified the synthesis of AgNPs and IMP-AgNPs. A Dose-dependent decrease happened in terms of the MIC values of IMP-AgNPs were also affected by the existence of resistant genes. Low cytotoxic was observed regarding AgNPs which lead to apoptosis. The histopathological results showed a considerable epithelization in treated groups with IMPAgNPs. Accordingly, IMP-AgNPs can be considered as a powerful antibacterial agent to treat the infections caused by multidrug-resistant P. aeruginosa.

Clinical characteristics and outcome of hospitalized COVID-19 patients with diabetes: A single-center, retrospective study in Iran

AIM

To describe the epidemiological and clinical characteristics along with outcomes of hospitalized Coronavirus Disease 2019 (COVID-19) patients with and without diabetes.

METHODS

This retrospective, single-center study included 595 consecutive hospitalized patients with confirmed COVID-19 at Baqiyatallah Hospital in Tehran, Iran, from February 26, 2020 to March 26, 2020. Demographic data, clinical, laboratory, and radiological findings were collected and compared between patients based on diabetes status. Complications and clinical outcomes were followed up until April 4, 2020.

RESULTS

From among the 595 hospitalized patients with COVID-19, the median age was 55 years and 401 (67.4%) were male. The most common symptoms included fever (419 [70.4%]), dry cough (368 [61.8%]) and dyspnea (363 [61%]). A total of 148 patients (24.9%) had diabetes, and compared with patients without diabetes, these patients had more comorbidities (eg, hypertension [48.6% vs. 22.3%; P < 0.001]); had higher levels of white blood cell count, neutrophil count, C-reactive protein, erythrocyte sedimentation rate and blood urea nitrogen, and had a higher proportion of patchy ground-glass opacity in chest computed tomography findings (52.7% vs. 25.7%; P < 0.001). Significantly, patients with diabetes had more complications and needed more respiratory support than those without diabetes (P < 0.001). At the end of the follow-up, treatment failure and death was significantly higher in patients with diabetes compared to those without diabetes (17.8% vs. 8.7%; P = 0.003).

CONCLUSION

COVID-19 patients with diabetes are at a higher risk of complications and a higher in-hospital mortality during hospitalization. Diabetes status of COVID-19 patients and frequent monitoring of glycemia would be helpful to prevent deteriorating clinical conditions.

Integrative role of traditional and modern technologies to combat COVID-19

INTRODUCTION

With the development of various branches of sciences, we will be able to resolve different clinical aspects of various diseases better. The convergence of these sciences can potentially tackle the new corona crisis.

AREAS COVERED

In this review, we attempted to explore and describe various scientific branches studying COVID-19. We have reviewed the literature focusing on the prevention, diagnosis, and treatment of COVID-19. The primary databases targeted were Science Direct, Scopus and PubMed. The most relevant reports from the recent two decades were collected utilizing keywords including SARS-CoV, MERS-CoV, COVID-19, epidemiology, therapeutics and diagnosis.

EXPERT OPINION

Based on this literature review, both traditional and emerging approaches are vital for the prevention, diagnosis and treatment of COVID-19. The traditional sciences play an essential role in the preventive and supportive care of corona infection, and modern technologies appear to be useful in the development of precise diagnosis and powerful treatment approaches for this disease. Indeed, the integration of these sciences will help us to fight COVID-19 disease more efficiently.

Assessment of Susceptibility to Five Common Antibiotics and Their Resistance Pattern in Clinical Enterococcus Isolates

Background & Objective:

Enterococcus Species are the common cause of nosocomial infections, which are highly resistant to different antibiotics. Therefore, determination of their antibiotic susceptibility patterns and simultaneous resistance to antibiotics is important for better treatment strategies.

Methods:

400 clinical Enterococcus isolates were collected from different hospitals in Tehran, Iran. Standard phenotypic-biochemical tests and PCR were used to identify the Enterococcus species. The antimicrobial susceptibility patterns and simultaneous resistance to selected antibiotics were determined by disk diffusion method according to the CLSI guidelines. All data analysis was performed using Python packages Scipy and Stats models.

Results:

According to the biochemical and PCR analyses, among 400 Enterococcus species, 72% of samples were Enterococcus faecalis, 10.75% Enterococcus faecium, and 17.25% other Enterococcus species. The results determined antimicrobial resistances of these strains against gentamicin, vancomycin, fosfomycin trometamol, teicoplanin, and quinupristin/dalfopristin. Results confirmed a significant correlation between resistance to vancomycin and resistance to teicoplanin. This correlation remains significant when including only E. faecium or E. faecalis species. We also found a negative correlation between resistance to teicoplanin and quinupristin/dalfopristin. Additionally, Quinupristin/dalfopristin was the least effective antibiotic while vancomycin and teicoplanin were the most effective ones.

Conclusion:

Based on the results and association between simultaneous resistance to some antibiotics such as vancomycin and teicoplanin, in the case of antibiotic resistance, the choice of a second antibiotic can be very important which can lead to good or bad effects.

Engineered substrates with imprinted cell-like topographies induce direct differentiation of adipose-derived mesenchymal stem cells into Schwann cells

Differentiation of stem cells to Schwann is considered efficient way for nerve regeneration since the sources of human Schwann cells are limited for clinical application. It is demonstrated that mimicking micromechanical forces or micro/nanotopographical environments that stem cells are experienced in vivo could control their fate. Here, the potency of substrates with imprinted cell-like topographies for direct differentiation of adipose-derived mesenchymal stem cells (ADSCs) into Schwann cells (SCs) is reported. For the preparation of substrates with imprinted SC-Like topographies, SCs are isolated from the sciatic nerve, grown, fixed, and then SC morphologies are transferred to polydimethylsiloxane (PDMS) substrates by mold casting. Subsequently, mesenchymal stem cells (MSCs) are seeded on the SC-imprinted substrates and their differentiation to SCs is evaluated by immunocytochemistry, real-time PCR, and western blotting. Analysis of morphology and expression of SC-specific markers show that MSCs cultured on the imprinted substrates have the typical SC-like morphology and express SC-specific markers including S100b, p75NTR, and Sox10. It is believed that specific cell-like topographies and related micromechanical cues can be sufficient for direct differentiation of ADSCs into Schwann cells by cell-imprinting method as a physical technique.

Crosstalk between chitosan and cell signaling pathways

The field of tissue engineering (TE) experiences its most exciting time in the current decade. Recent progresses in TE have made it able to translate into clinical applications. To regenerate damaged tissues, TE uses biomaterial scaffolds to prepare a suitable backbone for tissue regeneration. It is well proven that the cell-biomaterial crosstalk impacts tremendously on cell biological activities such as differentiation, proliferation, migration, and others. Clarification of exact biological effects and mechanisms of a certain material on various cell types promises to have a profound impact on clinical applications of TE. Chitosan (CS) is one of the most commonly used biomaterials with many promising characteristics such as biocompatibility, antibacterial activity, biodegradability, and others. In this review, we discuss crosstalk between CS and various cell types to provide a roadmap for more effective applications of this polymer for future uses in tissue engineering and regenerative medicine.

Antimicrobial activity of an antimicrobial peptide against amastigote forms of Leishmania major

Zoonotic cutaneous leishmaniasis caused by Leishmania major is a most common type of vector-borne disease in Iran. The pentavalent antimonial drugs have been used in the treatment of cutaneous leishmaniasis for a long time, but drug resistance and some of serious side effects have been reported. Thus, discovery and development of new therapeutic candidates are needed. The CM11 peptide is one of these peptides that its anti-bacterial activity has been proven. This peptide is a short cecropin–melittin hybrid peptide obtained through a sequence combination approach. The aim of this study was to evaluate in vitro anti-leishmanial activity of CM11 peptide against amastigote forms of Leishmania major. In this study, amastigote forms of Iranian strain of L. major (MRHO/IR/75/ER) were cultured in the presence of different concentrations of meglumine antimoniate (Glucantime^®) to find the most appropriate in vitro concentration of Glucantime^® against L. major amastigotes. Then, the anti-leishmanial activities of various concentrations of CM11 peptide (8, 16, 32 and 64 µM) were evaluated for 24, 48 and 72 hr by DAPI staining. In addition, MTT assay was used to determine the cytotoxic effects of CM11 peptide on murine fibroblast cell line. The results showed that CM11 peptide has antimicrobial activity against Iranian isolate of L. major in the laboratory conditions. It seems that the CM11 peptide has significant potential to be used as a new anti-leishmanial agent.

Investigation of the antimicrobial activity of a short cationic peptide against promastigote and amastigote forms of Leishmania major (MHRO/IR/75/ER): An in vitro study

Cutaneous leishmaniasis is one of the most endemic global health problems in many countries all around the world. Pentavalent antimonial drugs constitute the first line of leishmaniasis treatment; however, resistance to these drugs is a serious problem. Therefore, new therapies with new modes of action are urgently needed. In the current study, we examined antimicrobial activity of CM11 hybrid peptide (WKLFKKILKVL-NH2) against promastigote and amastigote forms of L. major (MHRO/IR/75/ER). In vitro anti-leishmanial activity was identified against L. major by parasite viability and metabolic activity after exposure to different peptide concentration. In the presentt study, we demostrated that different concentrations of CM11 result in dose dependent growth inhibition of Leishmania promastigotes. Furthermore, we demostrated that CM11 peptide has significant anti-leishmanial activities on amastigotes. Our results demonstrated that CM11 antimicrobial peptide may provide an alternative therapeutic approach for L. major treatment.

Stem cell therapy for lung diseases: From fundamental aspects to clinical applications

The respiratory system is a complex group of organs in the human body, all of which are necessary in breathing. Due to its special anatomy and composition, after exposure to various damaging factors such as micro particles, carbon granules and toxic gases, the respiratory system can be affected by a variety of damage without return to its original state. Currently, the prevalence of lung diseases, including asthma, and chronic obstructive pulmonary diseases, such as emphysema, has increased remarkably. New therapeutic approaches are desperately needed to discover regenerative medicine approaches, especially cell therapy. This review summarizes the recent advances in stem cell treatments and the research efforts conducted through the application of stem cell therapy for respiratory system diseases. In particular, researchers have used animal models to gather data about treating lung injury by stem cell transplantation. This review concentrated on the findings about route, timing and adjustment of cell transplantation dose, optimum stem cell type selection and potency marker of cells as therapeutic agents. These factors are essential subjects for approval and clinical transplantation. The current clinical trials aiming at treatment of lung diseases by stem cells are mentioned and discussed.

Antimicrobial Peptides: Features, Action, and Their Resistance Mechanisms in Bacteria

In recent years, because of increased resistance to conventional antimicrobials, many researchers have started to study the synthesis of new antibiotics to control the disease-causing effects of infectious pathogens. Antimicrobial peptides (AMPs) are among the newest antibiotics; these peptides are integral compounds in all kinds of organisms and play a significant role in microbial ecology, and critically contribute to the innate immunity of organisms by destroying invading microorganisms. Moreover, AMPs may encourage cells to produce chemokines, stimulate angiogenesis, accelerate wound healing, and influence programmed cell death in multicellular organisms. Bacteria differ in their inherent susceptibility and resistance mechanisms to these peptides when responding to the antimicrobial effects of AMPs. Generally, the development of AMP resistance mechanisms is driven by direct competition between bacterial species, and host and pathogen interactions. Several studies have shown diverse mechanisms of bacterial resistance to AMPs, for example, some bacteria produce proteases and trapping proteins; some modify cell surface charge, change membrane fluidity, and activate efflux pumps; and some species make use of biofilms and exopolymers, and develop sensing systems by selective gene expression. A closer understanding of bacterial resistance mechanisms may help in developing novel therapeutic approaches for the treatment of infections caused by pathogenic organisms that are successful in developing extensive resistance to AMPs. Based on these observations, this review discusses the properties of AMPs, their targeting mechanisms, and bacterial resistance mechanisms against AMPs.

Natural antisense RNAs as mRNA regulatory elements in bacteria: a review on function and applications

Naturally occurring antisense RNAs are small, diffusible, untranslated transcripts that pair to target RNAs at specific regions of complementarity to control their biological function by regulating gene expression at the post-transcriptional level. This review focuses on known cases of antisense RNA control in prokaryotes and provides an overview of some natural RNA-based mechanisms that bacteria use to modulate gene expression, such as mRNA sensors, riboswitches and antisense RNAs. We also highlight recent advances in RNA-based technology. The review shows that studies on both natural and synthetic systems are reciprocally beneficial.

Identification and characterization of a cathepsin L-like cysteine protease from Rhipicephalus (Boophilus) annulatus

The tick Rhipicephalus (Boophilus) annulatus is one of the most important ectoparasites of bovines and is responsible for the transmission of different pathogens such as Babesia and Anaplasma. Cysteine proteases are involved in several host-tick interactions including invasion of host tissues, immune evasion, pathogen transmission, embryogenesis and blood digestion. In this study, the gene encoding R. annulatus cathepsin L-like enzyme (RaCL1) was cloned into pTZ57R/T vector, sequenced and analyzed using bioinformatics approaches. The nucleotide length of RaCL1 was 999 bp. Bioinformatics analysis showed 332 amino acids with an approximate molecular weight of 36.3 kDa which contained a signal peptide sequence (18 amino acids), pro-region (97 amino acids) and mature enzyme (217 amino acids). Multiple sequence alignment of the RaCL1 revealed high similarity to cathepsin L-like cysteine proteases from other tick species such as Rhipicephalus (Boophilus) microplus and Amblyomma variegatum. Based on bioinformatics analyses, results of this work suggest that RaCL1 can be a suitable candidate for the development of vaccine against R. annulatus.

Identification of novel bacterial DNA gyrase inhibitors: An in silico study

Owing to essential role in bacterial survival, DNA gyrase has been exploited as a validated drug target. However, rapidly emerging resistance to gyrase-targeted drugs such as widely utilized fluoroquinolones reveals the necessity to develop novel compounds with new mechanism of actions against this enzyme. Here, an attempt has been made to identify new drug-like molecules for Shigella flexneri DNA gyrase inhibition through in silico approaches. The structural similarity search was carried out using the natural product simocyclinone D8, a unique gyrase inhibitor, to virtually screen ZINC database. A total of 11830 retrieved hits were further screened for selection of high-affinity compounds by implementing molecular docking followed by investigation of druggability according to Lipinski's rule, biological activity and physiochemical properties. Among the hits initially identified, three molecules were then confirmed to have reasonable gyrase-binding affinity and to follow Lipinski's rule. Based on these in silico findings, three compounds with different chemical structures from previously identified gyrase inhibitors were proposed as potential candidates for the treatment of fluoroquinolone-resistant strains and deserve further investigations.

Analysis of Healing Effect of Alginate Sulfate Hydrogel Dressing Containing Antimicrobial Peptide on Wound Infection Caused by Methicillin-Resistant Staphylococcus aureus

BACKGROUND

Wound infections caused by methicillin-resistant Staphylococcus aureus are a health problem worldwide; therefore, it is necessary to develop new antimicrobial compounds. Considering broad-spectrum antimicrobial activity and low probability of drug resistance to peptides, applications these peptides are being studied extensively.

OBJECTIVES

In this study, to control drug release over time, an alginate sulfate-based hydrogel impregnated with the CM11 peptide as the antimicrobial agent was developed, and its healing effects were tested on skin infections caused by methicillin-resistant S. aureus strains in a mouse model.

MATERIALS AND METHODS

Minimum inhibitory and minimum bactericidal concentrations of the CM11 peptide and alginate hydrogel in combination with the peptide were determined. Forty mice were divided into 4 groups: 1 group as a negative control (without treatment; however, 5 mice received hydrogel dressing without peptide), 1 group as a positive control (2% mupirocin treatment), and 2 groups as test groups. To establish skin infection, 200 μL of bacterial suspension with 3 × 10(8) CFU/mL concentration was subcutaneously injected in the scapular region of the mice. On the basis of the in vitro minimal bactericidal concentration of the alginate hydrogel containing peptide for 15 clinical isolates, hydrogel containing 128 mg/L of peptide was used for wound dressing over an 8-day period.

RESULTS

The highest and lowest numbers of wounds were observed on day 2 in the negative and positive control groups, respectively. During the 8-day period, the positive control and hydrogel containing peptide treatment groups showed similar levels of wound healing.

CONCLUSIONS

This study showed that compared to standard drug treatment, treatment with hydrogel containing peptide had substantial antibacterial effects on S. aureus wound infections in mice.

Investigation of caspase-1 activity and interleukin-1β production in murine macrophage cell lines infected with Leishmania major

OBJECTIVE

To investigate the caspase-1 dependent inflammatory pathway activity and interleukin-1β (IL-1β) secretion in murine macrophage cell lines J774G8 infected with Leishmania major (L. major) using caspase-1 activity assay and ELISA.

METHODS

Novy-MacNeal-Nicolle biphasic medium was applied to produce promastigote form of L. major. Metacyclic promastigotes in the stationary phase were applied to infect macrophage. Caspase-1 activity and IL-1β secretion were assessed by the CPP32/caspase-1 fluorometric protease assay and ELISA IL-1β kits, respectively, with time intervals of 6, 18 and 30 h.

RESULTS

Our study showed an increase in caspase-1 activity and IL-1β secretion in infected samples compared to non-infected macrophages. The highest increase in IL-1β production was observed after 6 h of infection.

CONCLUSIONS

These results arise that the activation of inflammasome pathway could be one of the innate immunity pathways against L. major.

Comparison of bacterial biodiversity and enzyme production in three hypersaline lakes; urmia, howz-soltan and aran-bidgol

This research is a comparative study on the diversity of halophilic bacteria with hydrolytic activities in three significant hypersaline lakes; Urmia in the northwest and Howz-Soltan and Aran-Bidgol in the central desert in Iran. Isolated strains from these saline lakes were found to be halotolerant, moderately and extremely halophilic bacteria. The bacteria in each saline lake were able to produce different hydrolytic enzymes including amylase, protease, lipase, DNase, inulinase, xylanase, carboxy methyl cellulase, pectinase and pullulanase. 188, 302, 91 halophilic strains were isolated from Urmia Lake, Howz-Soltan and Aran-Bidgol playa, respectively. The numbers of Gram-positive strains were more than Gram-negatives, and among Gram-positive bacteria; spore-forming bacilli were most abundant. Due to the unique physico-chemical conditions of the lake environments, the hydrolytic activities of isolated strains were significantly different. For instance, isolated strains from Howz-Soltan playa did not produce pectinase, DNase, amylase, lipase and inulinase, while the isolates from Aran-Bidgol playa had a great ability to produce pectinase and DNase. The strains from Urmia Lake were also good producers of DNase but failed to show any chitinase activity. The diversity of halophilic bacteria from the mentioned three saline lakes was also determined using PCR-amplified 16S rRNA followed by phylogenetic analysis of the partial 16S rRNA sequences.

Cloning and expression of a region of vesicle associated membrane protein2 (VAMP2) gene and its use as a recombinant peptide substrate for assaying clostridial neurotoxins in contaminated biologicals

An assay for the endopeptidase activities of clostridial neurotoxins in contaminated biotherapeutic products has been developed. Based on a synthetic peptide substrate representing amino acid residues 60-94 of the intracellular vesicle associated membrane protein2 (VAMP2), RT-PCR was used to amplify the VAMP2 sequence. The extended insert was digested with EcoRI and SalI and ligated into pGEX4T-1 vector for construction of the pGEX4T-1/VAMP plasmid for expressing in Escherichia coli a fusion protein linked to glutathione S-transferase (GST). The fusion protein was purified by affinity chromatography and used in an ELISA assay for comparison with the commercially available synthetic VAMP peptide and rabbit polyclonal antiserum. The identity of the immunoreactivity of recombinant VAMP2 protein with the chemically synthesized peptide was demonstrated by western blot. Our results indicated that recombinant VAMP2 peptide not only reacted with specific polyclonal antibody in a dose-dependent manner, without any remarkable difference observed between the reactivity of the fusion protein and commercial VAMP2 segment peptide, but also cleaved by botulinum neurotoxin type B (BONT/B) after endopeptidase assay. Thus, recombinant VAMP2 could serve as a replacement for VAMP2 synthetic peptide, potentially useful in endopeptidase assays for replacement of the currently used mouse bioassay for clostridial neurotoxins contaminating biotherapeutic products.