Histological Studies on a Newly Isolated Bacillus subtilis D10 Protease in the Debridement of Burn Wound Eschars Using Mouse Model

A sulfated exopolysaccharide from Bacillus altitudinis MTCC13046 accelerates cutaneous wound healing via dermal fibroblast migration: Insights into an in vivo wound re-epithelialization

Bacterial exopolysaccharides with (1 → 3) linked β-glucans and β-galactans have been identified as potent candidates for wound healing. In this study, a sulfated exopolysaccharide (BAP-2), characterized by its major repeating units as [→3)-β-GlcAp-(1 → 3)-(2,6-di-O-SO3)-β-Galp-(1→], was isolated from seaweed-associated Bacillus altitudinis MTCC13046. Whole-genome analysis of B. altitudinis MTCC13046 revealed the presence of biosynthetic gene clusters coding for saccharin. BAP-2 demonstrated anti-inflammatory activity by downregulating the expressions of inflammatory cytokines, such as interferon (IFN)-γ (1.77-fold), interleukins (IL-2/1β/6/12), and tumor necrosis factor (TNF)-α (~87 %) along with nitric oxide (~45 %), while upregulating transforming growth factor-β (3.88-fold) in comparison with lipopolysaccharide-induced RAW 264.7 macrophage and human monocytic THP-1 cells. BAP-2 exhibited biocompatibility with dermal fibroblasts, promoting cell adhesion and proliferation by upregulating Ki-67 (fibroblast proliferation marker) (12.66-fold), epidermal growth factor (5.6-fold), and epithelial-cadherin expressions level (~6-fold), after 48 h. Cell cycle progression and cellular interaction studies showed that administration of BAP-2 promotes conversion of human dermal fibroblast cells into the S phase, highlighting its effect on cell proliferation. In vivo experiments demonstrated approximately 98 % wound closure in BAP-2 administered experimental rats along with re-epithelialization of injured tissue. The pharmaceutical characteristics of the (1 → 3)-linked sulfated exopolysaccharide (BAP-2) suggests it could be an effective candidate for the treatment of cutaneous wound.

Immortelle Essential-Oil-Enriched Hydrogel for Diabetic Wound Repair: Development, Characterization, and In Vivo Efficacy Assessment

Background: Alarming data revealed that 19% to 34% of adults with diabetes mellitus develop chronic wounds, which are characterized by impaired healing and a higher risk of infections. Inspired by the traditional use of immortelle for wound healing and the lack of scientific evidence regarding how it thoroughly influences tissue regeneration, we aimed to formulate a hydrogel loaded with immortelle essential oil and assess its effectiveness on diabetic excision wounds. Methods: The rheological properties of the hydrogel, an in vivo safety test, as well as wound healing capacity, were determined in rats with induced diabetes and excision wounds. Diabetic rats were divided into four groups: untreated, treated with 1% silver sulfadiazine ointment, treated with a gel base, and treated with the immortelle essential oil-based hydrogel. Results: It was revealed that the hydrogel exerts pseudoplastic behavior and has no potential to act as an irritant, thus highlighting its suitability for skin application. Moreover, analysis of macroscopic, biochemical, and histopathological data revealed that the immortelle essential oil-based hydrogel significantly improves wound repair. Superior re-epithelialization, scar maturation, and increased collagen fiber density were achieved after immortelle essential oil-based gel application. Conclusions: These findings suggest that the immortelle essential oil-based hydrogel could be a natural, safe, and effective wound-healing dressing.

Debridement efficacy of serine protease and formulated cream by In Vitro assessment against artificial wound eschar

Chronic wounds typically comprise of necrotic tissue and dried secretions, often culminating in the formation of a thick and tough layer of dead skin known as eschar. Removal of eschar is imperative to facilitate wound healing. Conventional approach for eschar removal involves surgical excision and grafting, which can be traumatic and frequently leads to viable tissue damage. There has been growing interest in the use of enzymatic agents for a gentler approach to debridement, utilizing proteolytic enzymes. In this study, a purified intracellular recombinant serine protease from Bacillus sp. (SPB) and its cream formulation were employed to evaluate their ability to degrade artificial wound eschar; composed of collagen, fibrin, and elastin. Degradation was assessed based on percentage weight reduction of eschar biomass, analysis via sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), and scanning electron microscopy (SEM). Both SPB and its cream formulation were able to degrade up to 50 % artificial wound eschar, with the SPB cream maintaining its degradation efficiency for up to 24 hours. Additionally, the SPB-based cream demonstrated the ability to hydrolyze proteinaceous components of eschars individually (fibrin and collagen) as determined through qualitative assessment. These findings suggest that SPB holds promise for the debridement of wound eschar.

In silico and experimental characterization of a new polyextremophilic subtilisin-like protease from Microbacterium metallidurans and its application as a laundry detergent additive

Considering the current growing interest in new and improved enzymes for use in a variety of applications, the present study aimed to characterize a novel detergent-stable serine alkaline protease from the extremophilic actinobacterium Microbacterium metallidurans TL13 (MmSP) using a combined in silico and experimental approach. The MmSP showed a close phylogenetic relationship with high molecular weight S8 peptidases of Microbacterium species. Moreover, its physical and chemical parameters computed using Expasy's ProtParam tool revealed that MmSP is hydrophilic, halophilic and thermo-alkali stable. 3D structure modelling and functional prediction of TL13 serine protease resulted in the detection of five characteristic domains: [catalytic subtilase domain, fibronectin (Fn) type-III domain, peptidase inhibitor I9, protease-associated (PA) domain and bacterial Ig-like domain (group 3)], as well as the three amino acid residues [aspartate (D182), histidine (H272) and serine (S604)] in the catalytic subtilase domain. The extremophilic strain TL13 was tested for protease production using agricultural wastes/by-products as carbon substrates. Maximum enzyme activity (390 U/gds) was obtained at 8th day fermentation on potato peel medium. Extracellular extract was concentrated and partially purified using ammonium sulfate precipitation methodology (1.58 folds purification fold). The optimal pH, temperature and salinity of MmSP were 9, 60 °C and 1 M NaCl, respectively. The MmSP protease showed broad pH stability, thermal stability, salt tolerance and detergent compatibility. In order to achieve the maximum stain removal efficacy by the TL 13 serine protease, the operation conditions were optimized using a Box-Behnken Design (BBD) with four variables, namely, time (15-75 min), temperature (30-60 °C), MmSP enzyme concentration (5-10 U/mL) and pH (7-11). The maximum stain removal yield (95 ± 4%) obtained under the optimal enzymatic operation conditions (treatment with 7.5 U/mL of MmSP during 30 min at 32 °C and pH9) was in good agreement with the value predicted by the regression model (98 ± %), which prove the validity of the fitted model. In conclusion, MmSP appears to be a good candidate for industrial applications, particularly in laundry detergent formulations, due to its high hydrophilicity, alkali-halo-stability, detergent compatibility and stain removal efficiency.

Comparison of digital and traditional skin wound closure assessment methods in mice

BACKGROUND

Chronic skin wounds are a common complication of many diseases such as diabetes. Various traditional methods for assessing skin wound closure are used in animal studies, including wound tracing, calliper measurements and histological analysis. However, these methods have poorly defined wound closure or practical limitations. Digital image analysis of wounds is an increasingly popular, accessible alternative, but it is unclear whether digital assessment is consistent with traditional methods. This study aimed to optimise and compare digital wound closure assessment with traditional methods, using a diabetic mouse model. Diabetes was induced in male C57BL/6J mice by high-fat diet feeding combined with low dose (65 mg/kg of body weight) streptozotocin injections. Mice fed normal chow were included as controls. After 18 weeks, four circular full-thickness dorsal skin wounds of 4 mm diameter were created per mouse. The wounds were photographed and measured by callipers. Wound closure rate (WCR) was digitally assessed by two reporters using two methods: wound outline (WCR-O) and re-epithelialisation (WCR-E). Wounded skin tissues were collected at 10-days post-wounding and wound width was measured from haematoxylin and eosin-stained skin tissue.

RESULTS

Between reporters, WCR-O was more consistent than WCR-E, and WCR-O correlated with calliper measurements. Histological analysis supported digital assessments, especially WCR-E, when wounds were histologically closed.

CONCLUSIONS

WCR-O could replace calliper measurements to measure skin wound closure, but WCR-E assessment requires further refinement. Small animal studies of skin wound healing can greatly benefit from standardised definitions of wound closure and more consistent digital assessment protocols.

Bacterial protease alleviate chronic liver fibrosis induced by thioacetamide through suppression of hepatic stellate cells consequently decrease its proliferative index

In chronic liver diseases, liver fibrosis occurs due to excessive extracellular matrix (ECM) protein accumulation. Approximately 2 million deaths occur yearly due to liver disease, while cirrhosis is the 11th most common cause of death. Therefore, newer compounds or biomolecules must be synthesized to treat chronic liver diseases. In this aspect, the present study focuses on the assessment of the anti-inflammatory and antioxidant impact of Bacterial Protease (BP) produced by a new mutant strain of bacteria (Bacillus cereus S6-3/UM90) and 4,4'-(2,5-dimethoxy-1,4-phenylene) bis (1-(3-ethoxy phenyl)-1H-1,2,3-triazole) (DPET) in the treatment of early stage of liver fibrosis induced by thioacetamide (TAA). Sixty male rats were divided into six groups, ten rats each as follows: (1) Control group, (2) BP group, (3) TAA group, (4) TAA-Silymarin (S) group, (5) TAA-BP group, and (6) TAA-DPET group. Liver fibrosis significantly elevated liver function ALT, AST, and ALP, as well as anti-inflammatory interleukin 6 (IL-6) and VEGF. The oxidative stress parameters (MDA, SOD, and NO) were significantly increased with a marked reduction in GSH. Expression of MAPK and MCP-1 was unregulated in the TAA group, with downregulation of Nrf₂ was observed. TAA caused histopathological alterations associated with hepatic vacuolation and fibrosis, increasing collagen fibers and high immuno-expression of VEGF. On the other hand, treatment with BP successfully improved the severe effects of TAA on the liver and restored histological architecture. Our study concluded the protective potentials of BP for attenuating liver fibrosis and could be used as adjuvant therapy for treating hepatic fibrosis.

New Advances in the Understanding of Proteases as Diagnostic and Pharmaceutical Targets in Homeostatic and Pathologic Conditions

Protease biology represents a hot topic in biomedical research because of their pivotal role in regulating cell and tissue homeostasis, regeneration and pathogenesis [...]

The Use of Menthol in Skin Wound Healing-Anti-Inflammatory Potential, Antioxidant Defense System Stimulation and Increased Epithelialization

Wound healing involves inflammatory, proliferative, and remodeling phases, in which various cells and chemical intermediates are involved. This study aimed to investigate the skin wound healing potential of menthol, as well as the mechanisms involved in its effect, after 3, 7, or 14 days of treatment, according to the phases of wound healing. Skin wound was performed in the back of Wistar rats, which were topically treated with vehicle cream; collagenase-based cream (1.2 U/g); or menthol-based cream at 0.25%, 0.5%, or 1.0% over 3, 7, or 14 days. Menthol cream at 0.5% accelerated the healing right from the inflammatory phase (3 days) by decreasing mRNA expression of inflammatory cytokines TNF-α and Il-6. At the proliferative phase (7 days), menthol 0.5% increased the activity of antioxidant enzymes SOD, GR, and GPx, as well as the level of GSH, in addition to decreasing the levels of inflammatory cytokines TNF-α, IL-6, and IL-1β and augmenting mRNA expression for Ki-67, a marker of cellular proliferation. At the remodeling phase (14 days), levels of inflammatory cytokines were decreased, and the level of Il-10 and its mRNA expression were increased in the menthol 0.5% group. Menthol presented skin wound healing activity by modulating the antioxidant system of the cells and the inflammatory response, in addition to stimulating epithelialization.

In vitro and in silico characterization of alkaline serine protease from Bacillus subtilis D9 recovered from Saudi Arabia

In this study, we have isolated and characterized proteolytic soil bacteria and their alkaline protease. Based on 16S rRNA sequence analysis, 12 isolates with the highest protease activity were classified as B. subtilis and B. cereus groups. B. subtilis D9 isolate showing the highest protease activity was selected for in vitro and in silico analysis for its ِِAKD9 protease. The enzyme has a molecular mass of 48 kDa, exhibiting optimal activity at 50 °C pH 9.5, and showed high stability till 65 °C and pH 8-11 for 1 h. Fe3+‏ stimulated, but Zn2+ and Hg2+ strongly inhibited the protease activity. Also, the maximum inhibition with PMSF indicated serine protease-type of AKD9 protease. AkD9 alkaline serine protease gene showed high sequence similarity and close phylogenetic relationship with AprX serine protease of B. subtilis isolates. Functional prediction of AKD9 resulted in the detection of subtilase domain, peptidase_S8 family, and subtilase active sites. Moreover, prediction of physicochemical properties indicated that AKD9 serine protease is hydrophilic, thermostable, and alkali-halo stable. Secondary structure prediction revealed the dominance of the coils enhances AKD9 activity and stability under saline and alkaline conditions. Based on molecular docking, AKD9 showed very promising binding affinities towards casein substrate with expected intrinsic proteolytic activities matching our obtained in vitro results. In conclusion, AKD9 alkaline serine protease seems to be a significant candidate for industrial applications because of its stability, hydrophilicity, enhanced thermostability, and alkali-halo stability.