Serratiopeptidase: a well-known metalloprotease with a new non-proteolytic activity against S. aureus biofilm

Serratiopeptidase exhibits antibiofilm activity through the proteolytic function of N-terminal domain and versatile function of the C-terminal domain

BACKGROUND

Serratiopeptidase, a serine protease traditionally used as an oral anti-inflammatory drug has been found to show antibiofilm action. Structurally, it comprises of two distinct domains; viz-the N-terminal catalytic domain (Ncat) and a C-terminal RTX (Repeat-In-Toxin) domain (Crtx). Understanding the antibiofilm action of the serratiopeptidase molecule, as well as the antibiofilm action of each of its two domains, was the objective of this study.

RESULTS

Separate clones to express the complete recombinant serratiopeptidase protein and its variant containing a mutation in the catalytic site, the N-terminal catalytic domain and its mutant, and the C-terminal Repeat-In-Toxin domain were prepared, and the proteins were purified. The impact of these proteins on pre-existing biofilms, as well as their effect upon addition of these proteins during biofilm formation was investigated.

CONCLUSIONS

In our investigation, we have been able to analyze the antibiofilm action of serratiopeptidase in detail. Obtained results conclude that while N-terminally located proteolytic domain of serratiopeptidase conventionally acts against biofilms by hydrolytic activity, the C-terminal domain regulates or prevents biofilm formation by yet unknown mechanism in addition to its known function as an C-terminal located calcium modulated internal chaperone ensuring the proper folding and secretion of the molecule. The study's findings give new evidence that the Crtx domain plays a significant role in antibiofilm action. The proteolytic Ncat domain breaks down pre-formed biofilms. The C-terminal domain, on the other hand, acts as an inhibitor of biofilm formation by regulating or preventing biofilm development.

Secreted Metabolites from Pseudomonas, Staphylococcus, and Borrelia Biofilm: Modulation of Immunogenicity by a Nutraceutical Enzyme and Botanical Blend

Bacterial biofilms are hardy, adaptable colonies, evading immune recognition while triggering and sustaining inflammation. The goals for this study were to present a method for testing the immunogenicity of secreted metabolites from pathogenic biofilm and to document whether biofilm treated with a nutraceutical enzyme and botanical blend (NEBB) showed evidence of reprogrammed bacterial metabolism, potentially becoming more recognizable to the immune system. We screened immune-modulating properties of metabolites from established biofilm from Pseudomonas aeruginosa (Pa), Stapholycoccus simulans (Ss), and Borrelia burgdorferi (Bb). Secreted metabolites significantly increased the cytokine production by human peripheral blood mononuclear cells, including Interleukin-1-beta (IL-1β), Interleukin-6 (IL-6), macrophage inflammatory protein-1-alpha (MIP-1α), tumor necrosis factor-alpha (TNF-α), interleukin-1 receptor antagonist (IL-1ra), and interleukin-10 (IL-10). Pa metabolites triggered the most robust increase in IL-1β, whereas Bb metabolites triggered the most robust increase in IL-10. NEBB-disrupted biofilm produced metabolites triggering altered immune modulation compared to metabolites from untreated biofilm. Metabolites from NEBB-disrupted biofilm triggered increased MIP-1α levels and reduced IL-10 levels, suggesting a reduced ability to suppress the recruitment of phagocytes compared to untreated biofilm. The results suggest that nutraceutical biofilm disruption offers strategies for inflammation management in chronic infectious illnesses. Further clinical studies are warranted to evaluate clinical correlations in infected human hosts.

Calcium-induced structural transitions are central to the folding, function, and processing of serratiopeptidase zymogen into mature form

Serratia marcescens is an emerging health-threatening, gram-negative opportunistic pathogen associated with a wide variety of localized and life-threatening systemic infections. One of the most crucial virulence factors produced by S. marcescens is serratiopeptidase, a 50.2-kDa repeats-in-toxin (RTX) family broad-specificity zinc metalloprotease. RTX family proteins are functionally diverse exoproteins of gram-negative bacteria that exhibit calcium-dependent structural dynamicity and are secreted through a common type-1 secretion system (T1SS) machinery. To evaluate the impact of various divalent ligands on the folding and maturation of serratiopeptidase zymogen, the protein was purified and a series of structural and functional investigations were undertaken. The results indicate that calcium binding to the C-terminal RTX domain acts as a folding switch, triggering a disordered-to-ordered transition in the enzyme's conformation. Further, the auto-processing of the 16-amino acid N-terminal pro-peptide results in the maturation of the enzyme. The binding of calcium ions to serratiopeptidase causes a highly cooperative conformational transition in its structure, which is essential for the enzyme's activation and maturation. This conformational change is accompanied by an increase in solubility and enzymatic activity. For efficient secretion and to minimize intracellular toxicity, the enzyme needs to be in an unfolded extended form. The calcium-rich extracellular environment favors the folding and processing of zymogen into mature serratiopeptidase, i.e., the holo-form required by S. marcescens to establish infections and survive in different environmental niches.

Different levels of single-strain probiotic (Bacillus subtilis) with proteolytic enzyme (serratiopeptidase) can be used as an alternative to antibiotic growth promoters in broiler

In the current study, the proteolytic enzyme (serratiopeptidase) was used to enhance the efficacy of Bacillus subtilis (B. subtilis) probiotic as a growth promotor in broiler chicken. The effects of serratiopeptidase on the efficacy of different levels of B. subtilis as a growth promotor in broiler chicks were evaluated regarding growth performance traits, villus histomorphometric characterization, and intestinal microbiota count. Day-old broiler chicks (n = 120) were allocated into 4 groups having 3 replicates/group. In the control group (C), the basal diet was kept without supplementation. In treatment groups (P100, P150, and P200), the basal diet was supplemented with 100, 150, and 200 mg probiotics, respectively besides 30 mg proteolytic enzyme in the 3 treated groups for 4 wk. The performance parameters were significantly affected by the supplementation of serratiopeptidase to the B. subtilis treatment groups. Feed intake (FI), body weight gain (WG), feed conversion ratio (FCR), and dressing percent were significantly improved in the treatment groups as compared to the control group. Significantly, the lowest feed intake was recorded for the P200 group. The highest body weight gain and dressing percentage were recorded for the P200 group. An improved FCR was recorded in the P200 group (1.7) as compared to the control group. The different levels of B. subtilis supplemented with serratiopeptidase revealed significant improvements (P<0.05) in the morphology of the intestine by showing increases in villus height and width and crypt depth of the small intestine. The microbial count revealed that E. coli and salmonella colonies were significantly reduced in the P200 group as compared to the control and other treatment groups. In conclusion, the supplementation of B. subtilis with serratiopeptidase as a growth promoter in broiler chicks significantly improved the overall performance, and intestinal health and reduced microbial load contributing to optimizing the performance of broiler chickens. The greatest improvement was observed in the P200 group fed with B. subtilis as a probiotic and serratiopeptidase enzyme (200 mg:30 mg).

In vitro and in silico evaluation of the serrapeptase effect on biofilm and amyloids of Pseudomonas aeruginosa

Pseudomonas aeruginosa is an emerging threat for hospitalized and cystic fibrosis patients. Biofilm, a microbial community embedded in extracellular polymeric substance, fortifies bacteria against the immune system. In biofilms, the expression of functional amyloids is linked with highly aggregative, multi-resistant strains, and chronic infections. Serrapeptase (SPT), a protease possessing similar or superior anti-microbial properties with many antibiotics, presents anti-amyloid potential. However, studies on the employment of SPT against Pseudomonas biofilms and Fap amyloid, or the possible mechanisms of action are scarce. Here, SPT inhibited biofilm formation of P. aeruginosa ATCC 27853 on both plastic and glass surfaces, with an IC50 of 11.26 µg/mL and 0.27 µg/mL, respectively. The inhibitory effect of SPT on biofilm was also verified with optical microscopy of crystal violet-stained biofilms and with confocal microscopy. Additionally, SPT caused a dose-dependent decrease of bacterial viability (IC50 of 3.07 µg/mL) as demonstrated by MTT assay. Reduction of bacterial functional amyloids was also demonstrated, employing both fluorescence microscopy with thioflavin T and photometrical determination of Congo-red-positive compounds. Both viability and functional amyloids correlated significantly with biofilm inhibition. Finally, in silico molecular docking studies provided a mechanistic insight into the interaction of SPT with FapC or FapD, proving that both peptides are possible targets of SPT. These results offer new insights into the biofilm formation of P. aeruginosa and potentiate the involvement of SPT in the prevention and eradication of Pseudomonas biofilms. KEY POINTS: • Serrapeptase inhibits biofilm formation of P. aeruginosa on plastic and glass. • Biofilm inhibition correlated with reduced viability and functional amyloid levels. • In silico studies indicated that serrapeptase may target FapC and FapD peptides.

Fibrin and Fibrinolytic Enzyme Cascade in Thrombosis: Unravelling the Role

Blood clot formation in blood vessels (thrombosis) is a major cause of life-threatening cardiovascular diseases. These clots are formed by αA-, βB-, and ϒ-peptide chains of fibrinogen joined together by isopeptide bonds with the help of blood coagulation factor XIIIa. These clot structures are altered by various factors such as thrombin, platelets, transglutaminase, DNA, histones, and red blood cells. Various factors are used to dissolve the blood clot, such as anticoagulant agents, antiplatelets drugs, fibrinolytic enzymes, and surgical operations. Fibrinolytic enzymes are produced by microorganisms (bacteria, fungi, etc.): streptokinase of Streptococcus hemolyticus, nattokinase of Bacillus subtilis YF 38, bafibrinase of Bacillus sp. AS-S20-I, longolytin of Arthrobotrys longa, versiase of Aspergillus versicolor ZLH-1, etc. They act as a thrombolytic agent by either enhancing the production of plasminogen activators (tissue or urokinase types), which convert inactive plasminogen to active plasmin, or acting as plasmin-like proteins themselves, forming fibrin degradation products which cause normal blood flow again in blood vessels. Fibrinolytic enzymes may be classified in two groups, as serine proteases and metalloproteases, based on their catalytic properties, consisting of a catalytic triad responsible for their fibrinolytic activity having different physiochemical properties (such as molecular weight, pH, and temperature). The analysis of fibrinolysis helps to detect hyperfibrinolysis (menorrhagia, renal failure, etc.) and hypofibrinolysis (diabetes, obesity, etc.) with the help of various fibrinolytic assays such as a fibrin plate assay, fibrin microplate assay, the viscoelastic method, etc. These fibrinolytic activities serve as a key aspect in the recognition of numerous cardiovascular diseases and can be easily produced on a large scale with a short generation time by microbes and are less expensive.

Improved anti-biofilm activity and long-lasting effects of novel serratiopeptidase immobilized on cellulose nanofibers

Today, enzymatic treatment is a progressive field in combating biofilm producing pathogens. In this regard, serratiopeptidase, a medicinally important metalloprotease, has been recently highlighted as an enzyme with proved anti-biofilm activity. In the present study, in order to increase the long-lasting effects of the enzyme, serratiopeptidase and the novel engineered forms with enhanced anti-biofilm activity were immobilized on the surface of cellulose nanofibers (CNFs) as a natural polymer with eminent properties. For this, recombinant serratiopeptidases including the native and previously designed enzymes were produced, purified and conjugated to the CNF by chemical and physical methods. Immobilization was confirmed using different scanning and microscopic methods. The enzyme activity was assessed using casein hydrolysis test. Enzyme release analysis was performed using dialysis tube method. Anti-biofilm activity of free and immobilized enzymes has been examined on Staphylococcus aureus and Pseudomonas aeruginosa strains. Finally, cytotoxicity of enzyme-conjugated CNFs was performed by MTT assay. The casein hydrolysis results confirmed fixation of all recombinant enzymes on CNFs by chemical method; however, inadequate fixation of these enzymes was found using cold atmospheric plasma (CAP). The AFM, FTIR, and SEM analysis confirmed appropriate conjugation of enzymes on the surface of CNFs. Immobilization of enzymes on CNFs improved the anti-biofilm activity of serratiopeptidase enzymes. Interestingly, the novel engineered serratiopeptidase (T344 [8-339ss]) exhibited the highest anti-biofilm activity in both conjugated and non-conjugated forms. In conclusion, incorporation of serratiopeptidases into CNFs improves their anti-biofilm activities without baring any cytotoxicity. KEY POINTS: • Enzymes were successfully immobilized on cellulose nanofibers using chemical method. • Immobilization of enzymes on CNFs improved their anti-biofilm activity. • T344 [8-339ss] exhibited the highest anti-biofilm activity in both conjugated and non-conjugated forms.

Identification of potential mutational hotspots in serratiopeptidase to address its poor pH tolerance issue

Serratiopeptidase is the multifunctionality metalloendopeptidase extensively employed in biopharmaceutical and industrial biotechnology. Despite its poor pH tolerance, serratiopeptidase must withstand the highly acidic environment of the gastrointestinal tract to be used as a potent anti-inflammatory and analgesic medication. In earlier studies, post-translational deamination related mutations showed alteration in the net charge of protein's surface. Therefore, the current study aimed to enhance the acid resistance of serratiopeptidase via implementing computational interventions to screen out the most stable mutational hotspot. The methodology used in this study is as follows: (a) Higher accessibility to surface (b) 4 Å away from active site region to avoid interference with its proteolytic activity, and (c) By converting non-conserved amide residues to acidic residues. A docking study has been conducted to establish the substrate specificity and binding affinity to native and mutant proteins. The docking outcomes were then validated using molecular dynamic simulations to clarify each mutant's molecular stability and conformation while preserving their activity. The results showed that N412D is the best-screened mutant with negative electrostatic potential that can alter the overall charge on the protein's surface with increased H+ ions. Alteration in overall charge leads to protein surface more acidic that causes a common ion effect in stomach pH and act as a buffer which could stabilize the serratiopeptidase amid extreme pH.Communicated by Ramaswamy H. Sarma.

Serrapeptase impairs biofilm, wall, and phospho-homeostasis of resistant and susceptible Staphylococcus aureus

Staphylococcus aureus biofilms are implicated in hospital infections due to elevated antibiotic and host immune system resistance. Molecular components of cell wall including amyloid proteins, peptidoglycans (PGs), and lipoteichoic acid (LTA) are crucial for biofilm formation and tolerance of methicillin-resistant S. aureus (MRSA). Significance of alkaline phosphatases (ALPs) for biofilm formation has been recorded. Serrapeptase (SPT), a protease of Serratia marcescens, possesses antimicrobial properties similar or superior to those of many antibiotics. In the present study, SPT anti-biofilm activity was demonstrated against S. aureus (ATCC 25923, methicillin-susceptible strain, methicillin-susceptible S. aureus (MSSA)) and MRSA (ST80), with IC₅₀ values of 0.67 μg/mL and 7.70 μg/mL, respectively. SPT affected bacterial viability, causing a maximum inhibition of - 46% and - 27%, respectively. Decreased PGs content at [SPT] ≥ 0.5 μg/mL and ≥ 8 μg/mL was verified for MSSA and MRSA, respectively. In MSSA, LTA levels decreased significantly (up to - 40%) at lower SPT doses but increased at the highest dose of 2 μg/mL, a counter to spectacularly increased cellular and secreted LTA levels in MRSA. SPT also reduced amyloids of both strains. Additionally, intracellular ALP activity decreased in both MSSA and MRSA (up to - 85% and - 89%, respectively), while extracellular activity increased up to + 482% in MSSA and + 267% in MRSA. Altered levels of DING proteins, which are involved in phosphate metabolism, in SPT-treated bacteria, were also demonstrated here, implying impaired phosphorus homeostasis. The differential alterations in the studied molecular aspects underline the differences between MSSA and MRSA and offer new insights in the treatment of resistant bacterial biofilms. KEY POINTS: • SPT inhibits biofilm formation in methicillin-resistant and methicillin-susceptible S. aureus. • SPT treatment decreases bacterial viability, ALP activity, and cell wall composition. • SPT-treated bacteria present altered levels of phosphate-related DING proteins.

Serratiopeptidase: An integrated View of Multifaceted Therapeutic Enzyme

Microbial products have been used for the treatment of different diseases for many centuries. The serratiopeptidase enzyme provides a new hope for COVID-19-infected patients. Nowadays, anti-inflammatory drugs are easy to obtain at minimal expenditure from microbial sources. Serratia sp. is identified as one of the most efficient bacteria produced from serratiopeptidase. Screening for new and efficient bacterial strains from different sources has been of interest in recent years. Serratiopeptidase remains the most well-known anti-inflammatory drug of choice. Serratiopeptidase is a cheaper and safer anti-inflammatory drug alternative to NSAIDs. The multifaceted properties of serratiopeptidase may lead towards arthritis, diabetes, cancer and thrombolytic treatments. Existing serratiopeptidase treatments in combination with antibiotics are popular in the treatment of postoperative swelling. Although an exclusive number of serratiopeptidase-producing strains have been derived, there is an urge for new recombinant strains to enhance the production of the enzyme. This review explores the properties of serratiopeptidase, different therapeutic aspects, industrial production, and various analytical techniques used in enzyme recovery. In addition, the review highlights the therapeutic and clinical aspects of the serratiopeptidase enzyme to combat COVID-19-induced respiratory syndrome.

Design, expression and functional assessment of novel engineered serratiopeptidase analogs with enhanced protease activity and thermal stability

Serratiopeptidase is a bacterial protease that has been used medicinally in variety of applications. Though, some drawbacks like sensitivity to environmental conditions and low penetration into cells limited its usage as a potent pharmaceutical agent. This study aimed to produce four novel truncated serratiopeptidase analogs with different lengths and possessing one disulfide bridge, in order to enhance protease activity and thermal stability of this enzyme. Mutagenesis and truncation were performed using specific primers by conventional and overlap PCR. The recombinant proteins were expressed in E. coli cells then purified and their protease activity and stability were checked at different pH and temperatures in comparison to the native form of the enzyme, Serra473. Enzyme activity assay showed that T306 [12-302 ss] was not further active which could be due to the large truncation. However, T344 [8-339 ss], T380 [8-339 ss] and T380 [12-302 ss] proteins showed higher proteolytic activity comparing to Serra473. These analogs were active at temperatures of 25-90 °C and pH 6-9.5. Interestingly, remaining enzyme activity of T344 [8-339 ss], T380 [8-339 ss] and T380 [12-302 ss] forms at 90 °C calculated as 87, 83 and 86 percent, respectively, comparing to the activity at room temperature. However, residual activity at the same conditions was 50% for the full length enzyme. Formation of disulfide bond in engineered serratiopeptidases could be the main reason for higher thermal stability compared to Serra473. Thermostability of T344 [8-339 ss], as the most thermostable designed serratiopeptidase, was additionally confirmed using differential scanning calorimetry.

Gastrointestinal biofilms in health and disease

Microorganisms colonize various ecological niches in the human habitat, as they do in nature. Predominant forms of multicellular communities called biofilms colonize human tissue surfaces. The gastrointestinal tract is home to a profusion of microorganisms with intertwined, but not identical, lifestyles: as isolated planktonic cells, as biofilms and in biofilm-dispersed form. It is therefore of major importance in understanding homeostatic and altered host-microorganism interactions to consider not only the planktonic lifestyle, but also biofilms and biofilm-dispersed forms. In this Review, we discuss the natural organization of microorganisms at gastrointestinal surfaces, stratification of microbiota taxonomy, biogeographical localization and trans-kingdom interactions occurring within the biofilm habitat. We also discuss existing models used to study biofilms. We assess the contribution of the host-mucosa biofilm relationship to gut homeostasis and to diseases. In addition, we describe how host factors can shape the organization, structure and composition of mucosal biofilms, and how biofilms themselves are implicated in a variety of homeostatic and pathological processes in the gut. Future studies characterizing biofilm nature, physical properties, composition and intrinsic communication could shed new light on gut physiology and lead to potential novel therapeutic options for gastrointestinal diseases.

Staphylococcus aureus Internalization in Osteoblast Cells: Mechanisms, Interactions and Biochemical Processes. What Did We Learn from Experimental Models?

Bacterial internalization is a strategy that non-intracellular microorganisms use to escape the host immune system and survive inside the human body. Among bacterial species, Staphylococcus aureus showed the ability to interact with and infect osteoblasts, causing osteomyelitis as well as bone and joint infection, while also becoming increasingly resistant to antibiotic therapy and a reservoir of bacteria that can make the infection difficult to cure. Despite being a serious issue in orthopedic surgery, little is known about the mechanisms that allow bacteria to enter and survive inside the osteoblasts, due to the lack of consistent experimental models. In this review, we describe the current knowledge about S. aureus internalization mechanisms and various aspects of the interaction between bacteria and osteoblasts (e.g., best experimental conditions, bacteria-induced damages and immune system response), focusing on studies performed using the MG-63 osteoblastic cell line, the best traditional (2D) model for the study of this phenomenon to date. At the same time, as it has been widely demonstrated that 2D culture systems are not completely indicative of the dynamic environment in vivo, and more recent 3D models—representative of bone infection—have also been investigated.

A patent review of antibiofilm fungal drugs (2002-present)

Fungal biofilms, such as Candida albicans biofilms, are capable of surviving in hostile environments owing to their remarkable ability to adhere to surfaces and their tolerance to chemical interventions. Currently, therapeutic treatment options are few, making these biofilm-based infections problematic particularly due to their great tolerance to conventional antimicrobial drugs, thus causing serious health and economic problems. Therefore, the development of new drugs and antibiofilm specific therapies for the prevention and treatment of antifungal to eradicate biofilms are needed. This study was aimed at carrying out a patent review analysis to identify the innovation trends, and to explore the latest antifungal drugs and the specific therapeutic strategies available for the treatment of fungal biofilms. The present patent review was carried out using the Espacenet database, using the key words "biofilm and antifungal," from 2002 to December 2019. Through this review, it was possible to identify that most of the patent contents refer to new synthetic drugs derived from natural products and associations thereof with existing antifungal drugs. Methods and biomaterials for the treatment and prevention of fungal biofilms, mainly for C. albicans biofilms, which is the most isolated and studied fungal species, were also disclosed. The lack of scientific and technical information on the biofilm eradication subject is remarkable and further confirmed by the small number of patents identified in this survey.

Efficacy of Submucosal Injection of Chymotrypsin, Oral Serratiopeptidase or Oral Dexamethasone in Reducing Postoperative Complications Following Impacted Lower Third Molar Surgery: A Prospective, Randomized, Double-Blind, Controlled Clinical Trial

Aim The study aimed to compare between chymotrypsin, oral serratiopeptidase, and oral dexamethasone following impacted mandibular third molars surgery in respect of postoperative complications.

Materials and method: A randomized, double-blind clinical trial was conducted on 60 patients who were candidates for impacted mandibular third molars surgery and randomly allocated into the following 3 groups: submucosal chymotrypsin (5 mg), oral serratiopeptidase (10 mg), and oral dexamethasone (8 mg) (each group = 20). The outcome variables were postoperative pain (via visual analog scale), facial swelling (via tape method) and maximal mouth opening immediately after 2nd, 3rd, and 5th postoperative days.

Results: A total of 60 patients underwent randomization and allocation concealment and were included in the current study. All of the subjects tolerated the medicines with no untoward side or adverse effects. There was no statistically significant difference between the three groups in respect of postoperative pain intensity, facial swelling and maximal mouth opening at the immediate first hour, 2nd, 3rd, and 5th postoperative days (P < 0.05).

Conclusion: The present randomized clinical trial concluded that preemptive sub-mucosal injection of chymotrypsin yields a comparable effectiveness in decreasing postoperative sequelae following impacted mandibular third molars surgery when compared to oral serratiopeptidase or dexamethasone. This is the first Randomized Clinical Trail that assessed efficacy and safety of sub-mucosal injection of chymotrypsin after impacted mandibular third molars surgery. This trial is registered at clinicaltrials.in.th, number (TCTR20200828006).

Serratiopeptidase: Insights into the therapeutic applications

Therapeutic applications of enzymes have been widely accepted in clinical practices for decades. Proteolytic enzymes in particular, have been used for the treatment of diseases and disorders. Serratiopeptidase is a proteolytic enzyme having immense applications in therapeutic areas which have been validated by several in vitro, in vivo, and clinical studies as well as through anecdotal evidences. These applications are attributable to its versatile properties including anti-inflammatory, anti-biofilm, analgesic, anti-edemic, and fibrinolytic effects. The significant impact of serratiopeptidase reported needs to be backed by more scientific data. This review encompasses the details of therapeutic applications of serratiopeptidase based on available in vitro, in vivo, and clinical studies. We found some strong evidences regarding the efficacy of serratiopeptidase. However data on safety, tolerability, and its mechanism of action need detailing. This review aims to further explore the available literature on serratiopeptidase as well as provide scientific details for existing applications.

Production and Expression Optimization of Heterologous Serratiopeptidase

BACKGROUND

Serratiopeptidase is a bacterial metalloprotease, which is useful for the treatment of pain and inflammation. It breaks down fibrin, thins the fluids formed during inflammation and acts as an anti-biofilm agent. Because of medicinally important role of the enzyme, we aimed to study the cloning and the expression optimization of serratiopeptidase.

METHODS

The heat-stable serratiopeptidase (5d7w) was selected as the template. Cloning into pET28a expression vector was performed and confirmed by colony PCR and double restriction enzyme digestion. The recombinant protein was expressed in Esherichia coli BL21 and confirmed by SDS-PAGE and Western blot analysis. Different parameters such as expression vector, culture media, post-induction incubation temperature, inducer concentration, and post-induction incubation time were altered to obtain the highest amount of the recombinant protein.

RESULTS

Serratiopeptidase was successfully cloned and expressed under optimized conditions in E. coli which confirmed by western blot analysis. The optimal conditions of expression were determined using pQE30 as vector, cultivating the host bacteria in Terrific Broth (TB) medium, at 37° C, induction by IPTG concentration equal to 0.5 mM, and cells were harvested 4 h after induction.

CONCLUSION

As serratiopeptidase is a multi-potent enzyme, the expressed recombinant protein can be considered as a valuable agent for pharmaceutical applications in further studies.

The Process of Osteoblastic Infection by Staphylococcus Aureus

Bone infection is difficult to cure, and relapse frequently occurs, which is a major treatment problem. One of the main reasons for the refractory and recurrent nature of bone infection is that bacteria, such as Staphylococcus aureus (S. aureus), can be internalized into osteoblasts after infecting bone tissue, thereby avoiding attack by the immune system and antibiotics. Understanding how bacteria (such as S. aureus) are internalized into osteoblasts is key to effective treatment. S. aureus is the most common pathogenic bacterium that causes bone infection. This paper reviews the literature, analyzes the specific process of osteoblastic S. aureus infection, and summarizes specific treatment strategies to improve bone infection treatment.

Enhanced production of recombinant serratiopeptidase in Escherichia coli and its characterization as a potential biosimilar to native biotherapeutic counterpart

BACKGROUND

Serratia marcescens, a Gram-negative nosocomial pathogen secretes a 50 kDa multi-domain zinc metalloprotease called serratiopeptidase. Broad substrate specificity of serratiopeptidase makes it suitable for detergent and food processing industries The protein shows potent anti-inflammatory, anti-edemic, analgesic, antibiofilm activity and sold as an individual or fixed-dose enteric-coated tablets combined with other drugs. Although controversial, serratiopeptidase as drug is used in the treatment of chronic sinusitis, carpal tunnel syndrome, sprains, torn ligaments, and postoperative inflammation. Since the native producer of serratiopeptidase is a pathogenic microorganism, the current production methods need to be replaced by alternative approaches. Heterologous expression of serratiopeptidase in E. coli was tried before but not found suitable due to the limited yield, and other expression related issues due to its inherent proteolytic activity such as cytotoxicity, cell death, no expression, minimal expression, or inactive protein accumulation.

RESULTS

Recombinant expression of mature form serratiopeptidase in E. coli seems toxic and resulted in the failure of transformation and other expression related issues. Although E. coli C43(DE3) cells, express protein correctly, the yield was compromised severely. Optimization of protein expression process parameters such as nutrient composition, induction point, inducer concentration, post-induction duration, etc., caused significant enhancement in serratiopeptidase production (57.9 ± 0.73% of total cellular protein). Expressed protein formed insoluble, enzymatically inactive inclusion bodies, and gave 40-45 mg/l homogenous (> 98% purity) biologically active and conformationally similar serratiopeptidase to the commercial counterpart upon refolding and purification.

CONCLUSION

Expression of mature serratiopeptidase in E. coli C43(DE3) cells eliminated the protein expression associated with toxicity issues. Further optimization of process parameters significantly enhanced the overexpression of protein resulting in the higher yield of pure and functionally active recombinant serratiopeptidase. The biological activity and conformational features of recombinant serratiopeptidase were very similar to the commercially available counterpart suggesting it-a potential biosimilar of therapeutic and industrial relevance.

Purification and study of anti-cancer effects of Serratia marcescens serralysin

BACKGROUND AND OBJECTIVES

Serralysin is an extracellular metalloprotease from Serratia marcescens which has been the subject of extensive biological investigations. The goal of this study was to extract and purify serralysin from S. marcescens and to investigate its cytotoxic activity on the colorectal cancer cell line.

MATERIALS AND METHODS

The presence of the serralysin gene was confirmed using PCR. The supernatant of bacterial culture was collected and precipitated using ammonium sulfate. The precipitated protein was dialyzed and subjected to ion exchange chromatography for further purification. Casein assay and skim milk assay was used to confirm the enzymatic activity. SDS-PAGE was used to visualize the presence of serralysin. Metalloprotease inhibition activity was performed using 50 mM EDTA. Cytotoxic activity of serralysin was assessed on MTT assay.

RESULTS

The PCR product corresponding to serralysin was estimated to be approximately 1500 bp. A transparent zone around the bacterial colonies on skim milk agar and casein digestion confirmed the proteolytic activity of serralysin. A 52 kDa band in SDS-PAGE corresponding to serralysin was observed before and after purification processes. MTT assay showed IC50 values 24.78 μg/ml and 19.16 μg/ml after 24 h and 48 h exposure of Caco-2 cells to serralysin, respectively.

CONCLUSION

Our results showed that native serralysin has anticancer potential and may be a candidate for further pharmaceutical research and development. Further in vivo and in vitro mechanistic studies are suggested to confirm the biological activities.

Active thrombin produced by the intestinal epithelium controls mucosal biofilms

Proteolytic homeostasis is important at mucosal surfaces, but its actors and their precise role in physiology are poorly understood. Here we report that healthy human and mouse colon epithelia are a major source of active thrombin. We show that mucosal thrombin is directly regulated by the presence of commensal microbiota. Specific inhibition of luminal thrombin activity causes macroscopic and microscopic damage as well as transcriptomic alterations of genes involved in host-microbiota interactions. Further, luminal thrombin inhibition impairs the spatial segregation of microbiota biofilms, allowing bacteria to invade the mucus layer and to translocate across the epithelium. Thrombin cleaves the biofilm matrix of reconstituted mucosa-associated human microbiota. Our results indicate that thrombin constrains biofilms at the intestinal mucosa. Further work is needed to test whether thrombin plays similar roles in other mucosal surfaces, given that lung, bladder and skin epithelia also express thrombin.

The roles played by thrombin in the human intestinal mucosa are unclear. Here, the authors show that the commensal microbiota modulates epithelial production of active thrombin, which controls biofilm growth and contributes to protection of the mucosa from bacterial invasion.

In vitro antimicrobial efficacy of laser exposed chlorpromazine against Gram-positive bacteria in planktonic and biofilm growth state

Aqueous chlorpromazine solutions exposed to 266 nm generated as fourth harmonic of Nd:YAG pulsed laser along time intervals from 1 min to 240 min were investigated for their antimicrobial activity against planktonic and adherent Gram-positive bacterial strains. Qualitative and quantitative assays based on microbiological methods and flow cytometry assays were performed to establish the minimum inhibitory and minimum biofilm eradication concentrations and to reveal some of the possible mechanisms of antimicrobial activity. Optimal irradiation conditions and combinations of photoproducts for achieving the best antimicrobial and antibiofilm effects are suggested. It was confirmed that chlorpromazine solutions irradiated for 15 min and 30 min have the best antimicrobial and antibiofilm activity against Staphylococcus aureus ATCC 6538, methicillin susceptible Staphylococcus aureus, methicillin resistant Staphylococcus aureus, Enterococcus faecium 17-VAR, Enterococcus faecalis 2921, and Bacillus subtilis 6633. Flow cytometry revealed that two of the possible mechanisms of the antimicrobial activity of irradiated chlorpromazine are the inhibition of efflux pumps activity and induction of cellular membrane lesions.

Computational design, structure refinement and molecular dynamics simulation of novel engineered serratiopeptidase analogs

Communicated by Ramaswamy H. Sarma.

CpxR-Dependent Thermoregulation of Serratia marcescens PrtA Metalloprotease Expression and Its Contribution to Bacterial Biofilm Formation

PrtA is the major secreted metalloprotease of Serratia marcescens Previous reports implicate PrtA in the pathogenic capacity of this bacterium. PrtA is also clinically used as a potent analgesic and anti-inflammatory drug, and its catalytic properties attract industrial interest. Comparatively, there is scarce knowledge about the mechanisms that physiologically govern PrtA expression in Serratia In this work, we demonstrate that PrtA production is derepressed when the bacterial growth temperature decreases from 37°C to 30°C. We show that this thermoregulation occurs at the transcriptional level. We determined that upstream of prtA, there is a conserved motif that is directly recognized by the CpxR transcriptional regulator. This feature is found along Serratia strains irrespective of their isolation source, suggesting an evolutionary conservation of CpxR-dependent regulation of PrtA expression. We found that in S. marcescens, the CpxAR system is more active at 37°C than at 30°C. In good agreement with these results, in a cpxR mutant background, prtA is derepressed at 37°C, while overexpression of the NlpE lipoprotein, a well-known CpxAR-inducing condition, inhibits PrtA expression, suggesting that the levels of the activated form of CpxR are increased at 37°C over those at 30°C. In addition, we establish that PrtA is involved in the ability of S. marcescens to develop biofilm. In accordance, CpxR influences the biofilm phenotype only when bacteria are grown at 37°C. In sum, our findings shed light on regulatory mechanisms that fine-tune PrtA expression and reveal a novel role for PrtA in the lifestyle of S. marcescensIMPORTANCE We demonstrate that S. marcescens metalloprotease PrtA expression is transcriptionally thermoregulated. While strongly activated below 30°C, its expression is downregulated at 37°C. We found that in S. marcescens, the CpxAR signal transduction system, which responds to envelope stress and bacterial surface adhesion, is activated at 37°C and able to downregulate PrtA expression by direct interaction of CpxR with a binding motif located upstream of the prtA gene. Moreover, we reveal that PrtA expression favors the ability of S. marcescens to develop biofilm, irrespective of the bacterial growth temperature. In this context, thermoregulation along with a highly conserved CpxR-dependent modulation mechanism gives clues about the relevance of PrtA as a factor implicated in the persistence of S. marcescens on abiotic surfaces and in bacterial host colonization capacity.

Serratiopeptidase reduces the invasion of osteoblasts by Staphylococcus aureus

Finding new strategies to counteract periprosthetic infection and implant failure is a main target in orthopedics. Staphylococcus aureus, the leading etiologic agent of orthopedic implant infections, is able to enter and kill osteoblasts, to stimulate pro-inflammatory chemokine secretion, to recruit osteoclasts, and to cause inflammatory osteolysis. Moreover, by entering eukaryotic cells, staphylococci hide from the host immune defenses and shelter from the extracellular antibiotics. Thus, infection persists, inflammation thrives, and a highly destructive osteomyelitis occurs around the implant. The ability of serratiopeptidase (SPEP), a metalloprotease by Serratia marcescens, to control S. aureus invasion of osteoblastic MG-63 cells and pro-inflammatory chemokine MCP-1 secretion was evaluated. Human osteoblast cells were infected with staphylococcal strains in the presence and in the absence of SPEP. Cell proliferation and cell viability were also evaluated. The release of pro-inflammatory chemokine MCP-1 was evaluated after the exposure of the osteoblast cells to staphylococcal strains. The significance of the differences in the results of each test and the relative control values was determined with Student's t-test. SPEP impairs their invasiveness into osteoblasts, without affecting the viability and proliferation of bone cells, and tones down their production of MCP-1. We recognize SPEP as a potential tool against S. aureus bone infection and destruction.

Genome-based analysis of virulence determinants of a Serratia marcescens strain from soft tissues following a snake bite

AIM

Serratia marcescens wound infection after snakebite is often associated with aggressive presentations. However, the virulence determinants remain understudied.

MATERIALS & METHODS

Whole-genome sequencing was performed on S. marcescens VGH107, an isolate from wound infection secondary to Trimeresurus mucrosquamatus bite. Comparative genomics approach coupled with multivirulent-locus sequencing typing was applied to systematically predict potential virulence factors.

RESULTS

Multivirulent-locus sequencing typing indicated VGH107 falls within the cluster of high pathogenic strains. Comparative analysis identified virulence genes unique in VGH107, including ecpD and ecpE genes for periplasmic chaperone-pilus subunit complex and cdiA and cdiB genes for contact-dependent growth inhibition system.

CONCLUSION

The data established here provide foundation for further research regarding the virulence and resistance of S. marcescens.

Analytical techniques for serratiopeptidase: A review

A review is presented on different analytical techniques used for qualitative and quantitative analysis of serratiopeptidase, a proteolytic enzyme, which has recently gained importance as an anti-inflammatory agent. Efforts have been made to collate all the relevant references to the extent possible. The review discusses the advantages and disadvantages of the cited analytical techniques, which will help to give insights into the methods used for estimation of serratiopeptidase as such, from clinical isolates and from its dosage forms. The review highlights the basic as well as advanced techniques performed for estimating serratiopeptidase. The techniques illustrated here have been demonstrated to be useful for qualitative and quantitative determination of serratiopeptidase and may find application in analyzing other related proteases.

Role of Serratiopeptidase After Surgical Removal of Impacted Molar: A Systematic Review and Meta-analysis

Background

Serratiopeptidase for pain, facial swelling and trismus associated with surgical removal of impacted molar is under investigation. However conclusive evidence on the use of serratiopeptidase is lacking. Hence a systematic review and meta-analysis of randomized controlled studies was carried out.

Methods

Electronic databases were searched for eligible studies and necessary data extracted. The data were analysed using non-Cochrane mode in RevMan 5.0. 95% confidence interval (95% CI) was used to represent the deviation from the point estimate. The heterogeneity between the studies was assessed using Forest plot visually, I² statistics and Chi square test with a statistical P value of <0.10 to indicate statistical significance. Random-effect models were used in case of moderate to severe heterogeneity.

Results

Five studies were included for final review. Serratiopeptidase improved trismus better than corticosteroids with the MD, 95% as 4.42 [3.84, 5]. As regards to swelling, no significant difference was observed for serratiopeptidase when compared to corticosteroids. Paucity of studies precludes any conclusion for other outcome measures as well as for other comparator drugs.

Conclusion

Serratiopeptidase could be used safely and effectively to improve trismus and facial swelling after surgical removal of impacted molar.

Reduced Dental Plaque Formation in Dogs Drinking a Solution Containing Natural Antimicrobial Herbal Enzymes and Organic Matcha Green Tea

The results of an exploratory, multicenter clinical study confirmed the hypothesis that a novel, natural, and safe oral care product (OCP) reduced the rate of plaque formation on teeth of dogs consuming the OCP (antimicrobial plant-derived enzymes, organic matcha green tea, cultured dextrose, sodium bicarbonate, and ascorbic acid) compared to controls. Healthy dogs without periodontitis, of varying breeds, sex, and age, were recruited and enrolled, using nonrandomized stratification methods, into a control and treatment groups. Treatment group dogs drank only water into which OCP was suspended, for 28 days. Control group dogs drank their normal household water. On day 0 all teeth were cleaned by a veterinarian and gingivitis was assessed. On days 14, 21, and 28 plaque index, plaque thickness, gingivitis, freshness of breath, and general health were assessed. Over the 28 days of study, dogs on the OCP had significant reduction in plaque index and plaque thickness compared to controls. By day 14 OCP reduced plaque formation by 37%; the 28-day reduction in plaque index and coverage averaged 22% with no measurable gingivitis or calculus. Conclusion. Using the OCP attenuated dental plaque formation when consumed as normal drinking water and in the absence of other modes of oral care.