Validation of Matrix Metalloproteinase-9 (MMP-9) as a Novel Target for Treatment of Diabetic Foot Ulcers in Humans and Discovery of a Potent and Selective Small-Molecule MMP-9 Inhibitor That Accelerates Healing

Targeting Matrix Metalloproteinase-9 for Therapeutic Intervention in Diabetic Foot Ulcers

Diabetic foot ulcers (DFUs) are a complication of diabetes that have long been neglected. To date, a single drug (becaplermin containing platelet-derived growth factor, PDGF) has been approved by the FDA 27 years ago; however, it is seldom used because of its modest efficacy. The standard-of-care for DFUs is debridement, off-loading, and infection control with antibiotics, with hyperbaric oxygen (HBO) therapy being the treatment of last recourse. The paucity of understanding what accelerates diabetic wound healing results in more than 150,000 lower-limb amputations in the United States every year. A new paradigm for treatment of DFUs is proposed based on the higher levels of active matrix metalloproteinase (MMP)-9 with the more severe and infected human DFUs, and the demonstrated detrimental role of MMP-9 and the beneficial repair role of MMP-8 in diabetic mice. Selective inhibition of MMP-9 with the small molecule (R)-ND-336 lowered inflammation, reduced reactive oxygen species (ROS), and increased angiogenesis, without affecting MMP-8 to allow the natural repair mechanisms to take place. (R)-ND-336 showed better efficacy than becaplermin in diabetic mice. Becaplermin (PDGF) and HBO therapy work by decreasing MMP-9, but they do not completely suppress MMP-9 activity.

Revealing the molecular mechanisms in wound healing and the effects of different physiological factors including diabetes, age, and stress

Wounds are the common fates in various microbial infections and physical damages including accidents, surgery, and burns. In response, a healthy body with a potent immune system heals that particular site within optimal time by following the coagulation, inflammation, proliferation, and remodeling phenomenon. However, certain malfunctions in the body due to various diseases particularly diabetes and other physiological factors like age, stress, etc., prolong the process of wound healing through various mechanisms including the Akt, Polyol, and Hexosamine pathways. The current review thoroughly explains the wound types, normal wound healing mechanisms, and the immune system's role. Moreover, the mechanistic role of diabetes is also elaborated comprehensively.

Hypochlorous Acid for Wound Healing in Diabetic Rats: Effect on MMP-9 and Histology

Background

People who suffered type 2 diabetes have impaired healing of wounds due to the large number of circulating inflammatory cells resulting from high blood sugar levels. The wound healing process involves various complex processes including the degradation of extracellular matrix, a process characterized by an increase in matrix metalloproteinase-9 (MMP-9). Conventional management of diabetic wounds usually involves systemic blood sugar control and topical antimicrobial treatment, including hydrogen peroxide and povidone-iodine, which are known to be cytotoxic to the cells involved in the wound healing cascade. Finding a safe, non-toxic, and effecting wound cleansing still poses a challenge, and hypochlorous acid (HOCl) could act as a potential candidate.

Purpose

Unveiling an HOCl ion as an agent for diabetic wound management and MMP-9 as a marker for delayed diabetic wound healing.

Methods

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Flow Diagram is used to find and select related, eligible literatures for the review. The authors used several databases such as Pro Quest, Scopus, Springer link and Science Direct. In addition, and to expand the data, the database on Google Scholar was also opened. Then, the compiled data are analyzed to form results and discussions to the research question.

Results

Five eligible articles passed the inclusion criteria and reviewed for data synthesis. From 5 pieces of literature, it was found that the use of HOCl ions can be a good choice of topical agent in the management of diabetic wounds and decrease the activity of MMP-9, which act as a marker for delayed healing of diabetic wounds.

Conclusion

Topical agent, in this case HOCl ion, shows good results and can be used as an option in the management of diabetic wounds and MMP-9 can be used as a predictive marker in the management of diabetic wounds.

Water-powered, electronics-free dressings that electrically stimulate wounds for rapid wound closure

Chronic wounds affect ~2% of the U.S. population and increase risks of amputation and mortality. Unfortunately, treatments for such wounds are often expensive, complex, and only moderately effective. Electrotherapy represents a cost-effective treatment; however, its reliance on bulky equipment limits its clinical use. Here, we introduce water-powered, electronics-free dressings (WPEDs) that offer a unique solution to this issue. The WPED performs even under harsh conditions-situations wherein many present treatments fail. It uses a flexible, biocompatible magnesium-silver/silver chloride battery and a pair of stimulation electrodes; upon the addition of water, the battery creates a radial electric field. Experiments in diabetic mice confirm the WPED's ability to accelerate wound closure and promote healing by increasing epidermal thickness, modulating inflammation, and promoting angiogenesis. Across preclinical wound models, the WPED-treated group heals faster than the control with wound closure rates comparable to treatments requiring expensive biologics and/or complex electronics. The results demonstrate the WPED's potential as an effective and more practical wound treatment dressing.

Understanding and treating diabetic foot ulcers: Insights into the role of cutaneous microbiota and innovative therapies

Background

Notoriously known as the silent pandemic, chronic, non-healing diabetic foot ulcers (DFUs), pose a significant rate of incidence for amputation and are a major cause of morbidity. Alarmingly, the treatment and management strategies of chronic wounds represent a significant economic and health burden as well as a momentous drain on resources with billions per annum being spent in the US and UK alone. Defective wound healing is a major pathophysiological condition which propagates an acute wound to a chronic wound, further propelled by underlying conditions such as diabetes and vascular complications which are more prevalent amongst the elderly. Chronic wounds are prone to infection, which can exacerbate the condition, occasionally resulting in amputation for the patient, despite the intervention of modern therapies. However, amputation can only yield a 5-year survival rate for 50% of patients, highlighting the need for new treatments for chronic wounds.

Findings

The dynamic cutaneous microbiota is comprised of diverse microorganisms that often aid wound healing. Conversely, the chronic wound microbiome consists of a combination of common skin commensals such as Staphylococcus aureus and Staphylococcus epidermidis, as well as the opportunistic pathogen Pseudomonas aeruginosa. These bacteria have been identified as the most prevalent bacterial pathogens isolated from chronic wounds and contribute to prolific biofilm formation decreasing the efficiency of antimicrobials and further perpetuating a hyper-inflammatory state.

Discussion and Conclusion

Here, we review recent advances and provide a new perspective on alternative treatments including phage and microbiome transplant therapies and how the definitive role of the cutaneous microbiota impacts the aetiology of DFUs.

Machine learning and biological evaluation-based identification of a potential MMP-9 inhibitor, effective against ovarian cancer cells SKOV3

MMP-9, also known as gelatinase B, is a zinc-metalloproteinase family protein that plays a key role in the degradation of the extracellular matrix (ECM). The normal function of MMP-9 includes the breakdown of ECM, a process that aids in normal physiological processes such as embryonic development, angiogenesis, etc. Interruptions in these processes due to the over-expression or downregulation of MMP-9 are reported to cause some pathological conditions like neurodegenerative diseases and cancer. In the present study, an integrated approach for ML-based virtual screening of the Maybridge library was carried out and their biological activity was tested in an attempt to identify novel small molecule scaffolds that can inhibit the activity of MMP-9. The top hits were identified and selected for target-based activity against MMP-9 protein using the kit (Biovision K844). Further, MTT assay was performed in various cancer cell lines such as breast (MCF-7, MDA-MB-231), colorectal (HCT119, DL-D-1), cervical (HeLa), lung (A549) and ovarian cancer (SKOV3). Interestingly, one compound viz., RJF02215 exhibited anti-cancer activity selectively in SKOV3. Wound healing assay and colony formation assay performed on SKOV3 cell line in the presence of RJF02215 confirmed that the compound had a significant inhibitory effect on this cell line. Thus, we have identified a novel molecule that can inhibit MMP-9 activity in vitro and inhibits the proliferation of SKOV3 cells. Novel molecules based on the structure of RJF02215 may become a good value addition for the treatment of ovarian cancer by exhibiting selective MMP-9 activity.Communicated by Ramaswamy H. Sarma.

Molecular immunological mechanisms of impaired wound healing in diabetic foot ulcers (DFU), current therapeutic strategies and future directions

Diabetic foot ulcer (DFU) is a foremost cause of amputation in diabetic patients. Consequences of DFU include infections, decline in limb function, hospitalization, amputation, and in severe cases, death. Immune cells including macrophages, regulatory T cells, fibroblasts and other damage repair cells work in sync for effective healing and in establishment of a healthy skin barrier post-injury. Immune dysregulation during the healing of wounds can result in wound chronicity. Hyperglycemic conditions in diabetic patients influence the pathophysiology of wounds by disrupting the immune system as well as promoting neuropathy and ischemic conditions, making them difficult to heal. Chronic wound microenvironment is characterized by increased expression of matrix metalloproteinases, reactive oxygen species as well as pro-inflammatory cytokines, resulting in persistent inflammation and delayed healing. Novel treatment modalities including growth factor therapies, nano formulations, microRNA based treatments and skin grafting approaches have significantly augmented treatment efficiency, demonstrating creditable efficacy in clinical practices. Advancements in local treatments as well as invasive methodologies, for instance formulated wound dressings, stem cell applications and immunomodulatory therapies have been successful in targeting the complex pathophysiology of chronic wounds. This review focuses on elucidating the intricacies of emerging physical and non-physical therapeutic interventions, delving into the realm of advanced wound care and comprehensively summarizing efficacy of evidence-based therapies for DFU currently available.

Wound healing potential of Cystoseira/mesenchymal stem cells in immunosuppressed rats supported by overwhelming immuno-inflammatory crosstalk

Wound healing, one of the most intricate and dynamic processes of the body, maintains skin integrity following trauma. One of the main issues that still exists is impaired wound healing, particularly for immunosuppressed patients. Recently, natural products from marine environments have been employed in wound-repairing activities. This work investigates the mesenchymal stem cells in the combined capacity of the bone marrow (BMMSC) for wound healing and Cystoseira sp. Algae extract in immunosuppressed rats. High-resolution liquid chromatography / MS investigation of Cystoseira extract revealed the prevalence of fatty acids that have wound-soothing potential. From constructed PPI network for wound healing and further analysis through molecular docking and molecular dynamics (MD) simulation experiments suggested that cystalgerone metabolite may be responsible for the wound healing-promoting effect of Cystoseira extract. According to the CD marker characterization of the BMMSC, 98.21% of them expressed CD90, and 97.1% expressed CD105. Sixteen d after immunity suppression (by 40 mg/kg hydrocortisone daily), an incision was made in the dorsal skin of the rat. The treatments were applied for 16 d and samples were taken from the tested groups on the 8th, 14th, and 16th days. The BMMSCs / Cystoseira group showed significantly improved wound closure, thickness, density of new layers, and skin elasticity than the control group (p < 0.001). The BMMSCs / Cystoseira combination significantly reduced the oxidative indicators, pro-inflammatory cytokines, and immune markers, according to the RT-PCR gene expression study. In order to delve deeper into the complex interconnections among wound healing-related biological targets and pinpoint key factors in this complex process, we engaged in network pharmacology and computational research. Subsequently, we conducted a comprehensive computational analysis, including reverse docking, free energy (ΔG) computation, and molecular dynamics simulations, on the molecular structures of the annotated compounds. The purpose of this investigation was to identify potential new targets for these chemicals as well as any potential interactions they may have with different signaling pathways related to the wound healing process. Our research indicates that the primary compounds of Cystoseira holds potential wound healing therapeutic activity. Although more safety testing and clinical studies are required, the combination has great potential for regenerative medicine and could be a revolutionary advance in the healing of the wounds of immunosuppressed patients.

Natural Products as Regulators against Matrix Metalloproteinases for the Treatment of Cancer

Cancers are currently the major cause of mortality in the world. According to previous studies, matrix metalloproteinases (MMPs) have an impact on tumor cell proliferation, which could lead to the onset and progression of cancers. Therefore, regulating the expression and activity of MMPs, especially MMP-2 and MMP-9, could be a promising strategy to reduce the risk of cancers. Various studies have tried to investigate and understand the pathophysiology of cancers to suggest potent treatments. In this review, we summarize how natural products from marine organisms and plants, as regulators of MMP-2 and MMP-9 expression and enzymatic activity, can operate as potent anticancer agents.

Advancements in wound healing: integrating biomolecules, drug delivery carriers, and targeted therapeutics for enhanced tissue repair

Wound healing, a critical biological process vital for tissue restoration, has spurred a global market exceeding $15 billion for wound care products and $12 billion for scar treatment. Chronic wounds lead to delayed or impaired wound healing. Natural bioactive compounds, prized for minimal side effects, stand out as promising candidates for effective wound healing. In response, researchers are turning to nanotechnology, employing the encapsulation of these agents into drug delivery carriers. Drug delivery system will play a crucial role in enabling targeted delivery of therapeutic agents to promote tissue regeneration and address underlying issues such as inflammation, infection, and impaired angiogenesis in chronic wound healing. Drug delivery carriers offer distinct advantages, exhibiting a substantial ratio of surface area to volume and altered physical and chemical properties. These carriers facilitate sustained and controlled release, proving particularly advantageous for the extended process of wound healing, that typically comprise a diverse range of components, integrating both natural and synthetic polymers. Additionally, they often incorporate bioactive molecules. Despite their properties, including poor solubility, rapid degradation, and limited bioavailability, various natural bioactive agents face challenges in clinical applications. With a global research, emphasis on harnessing nanomaterial for wound healing application, this research overview engages advancing drug delivery technologies to augment the effectiveness of tissue regeneration using bioactive molecules. Recent progress in drug delivery has poised to enhance the therapeutic efficacy of natural compounds in wound healing applications.

Deciphering the crosstalk between inflammation and biofilm in chronic wound healing: Phytocompounds loaded bionanomaterials as therapeutics

In terms of the economics and public health, chronic wounds exert a significant detrimental impact on the health care system. Bacterial infections, which cause the formation of highly resistant biofilms that elude standard antibiotics, are the main cause of chronic, non-healing wounds. Numerous studies have shown that phytochemicals are effective in treating a variety of diseases, and traditional medicinal plants often include important chemical groups such alkaloids, phenolics, tannins, terpenes, steroids, flavonoids, glycosides, and fatty acids. These substances are essential for scavenging free radicals which helps in reducing inflammation, fending off infections, and hastening the healing of wounds. Bacterial species can survive in chronic wound conditions because biofilms employ quorum sensing as a communication technique which regulates the expression of virulence components. Fortunately, several phytochemicals have anti-QS characteristics that efficiently block QS pathways, prevent drug-resistant strains, and reduce biofilm development in chronic wounds. This review emphasizes the potential of phytocompounds as crucial agents for alleviating bacterial infections and promoting wound healing by reducing the inflammation in chronic wounds, exhibiting potential avenues for future therapeutic approaches to mitigate the healthcare burden provided by these challenging conditions.

Advanced multifunctional hydrogels for diabetic foot ulcer healing: Active substances and biological functions

AIM

Hydrogels with excellent biocompatibility and biodegradability can be used as the desirable dressings for the therapy of diabetic foot ulcer (DFU). This review aimed to summarize the biological functions of hydrogels, combining with the pathogenesis of DFU.

METHODS

The studies in the last 10 years were searched and summarized from the online database PubMed using a combination of keywords such as hydrogel and diabetes. The biological functions of hydrogels and their healing mechanism on DFU were elaborated.

RESULTS

In this review, hydrogels were classified by their active substances such as drugs, cytokines, photosensitizers, and biomimetic peptide. Based on this, the biological functions of hydrogels were summarized by associating the pathogenesis of DFU, including oxidative stress, chronic inflammation, cell phenotype change, vasculopathy, and infection. This review also pointed out some of the shortcomings of hydrogels in present researches.

CONCLUSIONS

Hydrogels were classified into carrier hydrogels and self-functioning hydrogels in this review. Besides, the functions and components of existing hydrogels were clarified to provide assistance for future researches and clinical applications.

Enhancing diabetic wound healing: advances in electrospun scaffolds from pathogenesis to therapeutic applications

Diabetic wounds are a significant subset of chronic wounds characterized by elevated levels of inflammatory cytokines, matrix metalloproteinases (MMPs), and reactive oxygen species (ROS). They are also associated with impaired angiogenesis, persistent infection, and a high likelihood of hospitalization, leading to a substantial economic burden for patients. In severe cases, amputation or even mortality may occur. Diabetic foot ulcers (DFUs) are a common complication of diabetes, with up to 25% of diabetic patients being at risk of developing foot ulcers over their lifetime, and more than 70% ultimately requiring amputation. Electrospun scaffolds exhibit a structural similarity to the extracellular matrix (ECM), promoting the adhesion, growth, and migration of fibroblasts, thereby facilitating the formation of new skin tissue at the wound site. The composition and size of electrospun scaffolds can be easily adjusted, enabling controlled drug release through fiber structure modifications. The porous nature of these scaffolds facilitates gas exchange and the absorption of wound exudate. Furthermore, the fiber surface can be readily modified to impart specific functionalities, making electrospinning nanofiber scaffolds highly promising for the treatment of diabetic wounds. This article provides a concise overview of the healing process in normal wounds and the pathological mechanisms underlying diabetic wounds, including complications such as diabetic foot ulcers. It also explores the advantages of electrospinning nanofiber scaffolds in diabetic wound treatment. Additionally, it summarizes findings from various studies on the use of different types of nanofiber scaffolds for diabetic wounds and reviews methods of drug loading onto nanofiber scaffolds. These advancements broaden the horizon for effectively treating diabetic wounds.

Multifunctional photothermally responsive hydrogel as an effective whole-process management platform to accelerate chronic diabetic wound healing

The management of chronic diabetic wounds is a complex issue that requires wound repair, regulation of inflammatory levels, and intervention to prevent bacterial infection. To address this issue, we developed a multifunctional photothermally responsive hydrogel (PAG-CuS) as an effective platform for managing the entire wound-healing process, including promoting wound healing, providing anti-inflammatory therapy, and performing photothermal sterilization. Constructed through copolymerization of acrylic acid (AA), methacrylic anhydride-modified gelatin (GelMA), and lipoic acid sodium (LAS) coated copper sulfide nanoparticles (CuS@LAS), PAG-CuS possessed a porous three-dimensional structure that promoted cell adhesion and had a substantial water-holding capacity. Additionally, the internal CuS@LAS not only conferred photothermal antibacterial properties to the hydrogel but also served as physical cross-linking agents, thus enhancing its mechanical strength. Under the NIR-induced photothermal effect, the porous hydrogel liberates CuS@LAS, and later CuS@LAS expels LAS via micelle deassembly to eliminate intracellular ROS. This results in the down-regulation of MMP-9 expression, promoting ECM production and facilitating wound healing. Meanwhile, the release of Cu2+ from PAG-CuS could enhance CD31 expression in endothelial cells, promoting microvessel formation, which is crucial for wound healing. In the diabetic wound model of GK rats, the PAG-CuS hydrogel reduced ROS levels, increased microvessel count, improved epithelialization, and enhanced wound healing. Therefore, this versatile photothermal hydrogel has the potential to be applied in sterilization, scavenging free radicals, and promoting angiogenesis, making it an effective and comprehensive solution to manage the challenges of diabetic wounds. STATEMENT OF SIGNIFICANCE: Assessment of functional recovery and timely adjustment of treatment strategy is critical in the management of chronic diabetic wounds. In this work, we prepared PAG-CuS composite hydrogels by integrating in situ reduction, chemical crosslinking, and nanoenhancement techniques. The near-infrared light-induced photothermal effect of PAG-CuS gel rapidly kills bacteria at the lesion site, and the generated heat simultaneously promotes the multilevel release of LAS from the gel, which could regulate the levels of ROS and MMP-9 to promote extracellular matrix formation. In addition, the Cu2+ released from the gel can promote the formation of blood vessels to improve blood oxygenation. Therefore, this project proposes a synergistic solution to realize the whole process of management to accelerate chronic diabetic wound healing.

Microenvironmental dynamics of diabetic wounds and insights for hydrogel-based therapeutics

The rising prevalence of diabetes has underscored concerns surrounding diabetic wounds and their potential to induce disability. The intricate healing mechanisms of diabetic wounds are multifaceted, influenced by ambient microenvironment, including prolonged hyperglycemia, severe infection, inflammation, elevated levels of reactive oxygen species (ROS), ischemia, impaired vascularization, and altered wound physicochemical properties. In recent years, hydrogels have emerged as promising candidates for diabetic wound treatment owing to their exceptional biocompatibility and resemblance to the extracellular matrix (ECM) through a three-dimensional (3D) porous network. This review will first summarize the microenvironment alterations occurring in the diabetic wounds, aiming to provide a comprehensive understanding of its pathogenesis, then a comprehensive classification of recently developed hydrogels will be presented, encompassing properties such as hypoglycemic effects, anti-inflammatory capabilities, antibacterial attributes, ROS scavenging abilities, promotion of angiogenesis, pH responsiveness, and more. The primary objective is to offer a valuable reference for repairing diabetic wounds based on their unique microenvironment. Moreover, this paper outlines potential avenues for future advancements in hydrogel dressings to facilitate and expedite the healing process of diabetic wounds.

Advances in Chronic Wound Management: From Conventional Treatment to Novel Therapies and Biological Dressings

Chronic wounds can be classified as diabetic foot ulcers, pressure ulcers, or venous leg ulcers. Chronic wound management has become a threat to clinicians and constitutes a major healthcare burden. The healing process of chronic wounds requires many factors to work in concert to achieve optimal healing. Various treatment options, ranging from hypoxia to infection, have evolved considerably to address the challenges associated with chronic wound healing. The conventional and accelerating treatments for chronic wounds still represent an unmet medical need due to the complex pathophysiology of the chronic wound microenvironment. In clinical settings, traditional chronic wound care practices rely on nonspecific topical treatment, which can reduce pain and alleviate disease progression with varying levels of success but fail to completely cure the wounds. Conventional wound dressings, such as hydrocolloids, gauze, foams, and films, have also shown limited success for the treatment of chronic wounds and only act as a physical barrier and absorb wound exudates. Emerging advances in treatment approaches, including novel therapies (stem cells, microRNAs, and nanocarrier-based delivery systems) and multifunctional biological dressings, have been reported for chronic wound repair. This review summarizes the challenges offered by chronic wounds and discusses recent advancements in chronic wound treatment.

Based on Clinical Research Matrix Metalloprotease (MMP) Inhibitors to Promote Diabetic Wound Healing

Chronic inflammation is a common factor in obesity, diabetes mellitus, and the complications of diabetes, including diabetic wounds. These ulcers are characterized by persistent lesions that are challenging to heal, significantly decreasing patients' quality of life and imposing a substantial financial burden on society. MMP are zinc endopeptidases that play a role in wound healing in response to various stimuli, including diabetes mellitus. MMP levels fluctuate throughout the wound healing process in diabetic patients' serum, skin tissues, and wound fluid, indicating their potential as biomarkers for diabetic foot ulcers. Targeting MMP has emerged as a promising strategy for treating diabetic wounds, as these enzymes are involved in critical biological processes related to wound healing, including extracellular matrix secretion, angiogenesis, granulation tissue formation, collagen growth, re-epithelization, inflammatory response, and oxidative stress.

Network pharmacology reveals the potential of Dolastatin 16 as a diabetic wound healing agent

Dolastatin 16, a marine cyclic depsipeptide, was initially isolated from the sea hare Dolabella Auricularia by Pettit et al. Due to the lack of information regarding its bioactivity, target identification becomes an indispensable strategy for revealing the potential targets and mechanisms of action of Dolastatin 16. Network pharmacology was utilized to identify targets associated with the disease, gene ontology, and KEGG pathways. The results highlighted Matrix Metalloproteinase-9 (MMP9) as a potential target of Dolastatin 16 through network pharmacology analysis. This target was found to be primarily involved in the TNF signaling pathway and in foot ulceration-associated diabetic polyneuropathy. Furthermore, the binding mode and dynamic behavior of the complex were investigated through molecular docking and molecular dynamics studies. In the docking study, a native ligand (a hydroxamate inhibitor) and (R)-ND-336 were employed as ligand controls, demonstrating binding energy values of - 6.6 and - 8.9 kcal/mol, respectively. The Dolastatin 16 complex exhibited a strong affinity for MMP9, with a binding energy value of - 9.7 kcal/mol, indicating its high potential as an inhibitor. Molecular dynamics also confirmed the stability of the MMP9-Dolastatin complex throughout the simulation process. Dolastatin 16 has the potential to act as an MMP9 inhibitor, offering promise for accelerating the wound healing process in diabetic foot conditions.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40203-023-00161-5.

The role of neutrophils in corneal nerve regeneration

BACKGROUND

To investigate the role of neutrophils in corneal nerve regeneration.

METHODS

A mouse model simulating corneal nerve injury was established and samples from corneal scraping with and without neutrophil closure were collected. These samples were used for corneal nerve staining, ribonucleic acid sequencing, and bioinformatics. Differential expression analysis was used to perform enrichment analysis to identify any significant differences between these two groups. The differential genes were then intersected with neutrophil-associated genes and a protein-protein interaction network was constructed using the intersected genes. The immune infiltration between the two groups was examined along with the immune cell variation between the high and low gene expression groups.

RESULTS

Neutrophil removal delays corneal epithelial and nerve regeneration. A total of 546 differential genes and 980 neutrophil-associated genes, with 27 genes common to both sets were obtained. Molecular Complex Detection analysis yielded five key genes, namely integrin subunit beta 2 (ITGB2), matrix metallopeptidase 9 (MMP9), epidermal growth factor (EGF), serpin family E member 1 (SERPINE1), and plasminogen activator urokinase receptor (PLAUR). Among these genes, ITGB2, SERPINE1, and PLAUR exhibited increased expression in the neutrophil-confined group, while MMP9 and EGF showed decreased expression, with MMP9 and EGF displaying a more significant difference. Immune infiltration was also observed between the two groups, revealing significant differences in the infiltration of M0 macrophages, activated mast cells, and neutrophils. Moreover, the neutrophil levels were lower in the groups with low MMP9 and EGF expressions and higher in the high-expression group.

CONCLUSION

Neutrophil confinement might significantly affect the MMP9 and EGF expression levels. Strategies to inhibit MMP9 could potentially yield therapeutic benefits.

Computational design of matrix metalloprotenaise-9 (MMP-9) resistant to auto-cleavage

Matrix metalloproteinase-9 (MMP-9) is an endopeptidase that remodels the extracellular matrix. MMP-9 has been implicated in several diseases including neurodegeneration, arthritis, cardiovascular diseases, fibrosis and several types of cancer, resulting in a high demand for MMP-9 inhibitors for therapeutic purposes. For such drug design efforts, large amounts of MMP-9 are required. Yet, the catalytic domain of MMP-9 (MMP-9Cat) is an intrinsically unstable enzyme that tends to auto-cleave within minutes, making it difficult to use in drug design experiments and other biophysical studies. We set our goal to design MMP-9Cat variant that is active but stable to auto-cleavage. For this purpose, we first identified potential auto-cleavage sites on MMP-9Cat using mass spectroscopy and then eliminated the auto-cleavage site by predicting mutations that minimize auto-cleavage potential without reducing enzyme stability. Four computationally designed MMP-9Cat variants were experimentally constructed and evaluated for auto-cleavage and enzyme activity. Our best variant, Des2, with 2 mutations, was as active as the wild-type enzyme but did not exhibit auto-cleavage after 7 days of incubation at 37°C. This MMP-9Cat variant, with an identical with MMP-9Cat WT active site, is an ideal candidate for drug design experiments targeting MMP-9 and enzyme crystallization experiments. The developed strategy for MMP-9CAT stabilization could be applied to redesign other proteases to improve their stability for various biotechnological applications.

Breakthrough treatments for accelerated wound healing

Skin injuries across the body continue to disrupt everyday life for millions of patients and result in prolonged hospital stays, infection, and death. Advances in wound healing devices have improved clinical practice but have mainly focused on treating macroscale healing versus underlying microscale pathophysiology. Consensus is lacking on optimal treatment strategies using a spectrum of wound healing products, which has motivated the design of new therapies. We summarize advances in the development of novel drug, biologic products, and biomaterial therapies for wound healing for marketed therapies and those in clinical trials. We also share perspectives for successful and accelerated translation of novel integrated therapies for wound healing.

Antioxidant Activities of Natural Compounds from Caribbean Plants to Enhance Diabetic Wound Healing

Diabetic wound healing is a global medical challenge. Several studies showed that delayed healing in diabetic patients is multifactorial. Nevertheless, there is evidence that excessive production of ROS and impaired ROS detoxification in diabetes are the main cause of chronic wounds. Indeed, increased ROS promotes the expression and activity of metalloproteinase, resulting in a high proteolytic state in the wound with significant destruction of the extracellular matrix, which leads to a stop in the repair process. In addition, ROS accumulation increases NLRP3 inflammasome activation and macrophage hyperpolarization in the M1 pro-inflammatory phenotype. Oxidative stress increases the activation of NETosis. This leads to an elevated pro-inflammatory state in the wound and prevents the resolution of inflammation, an essential step for wound healing. The use of medicinal plants and natural compounds can improve diabetic wound healing by directly targeting oxidative stress and the transcription factor Nrf2 involved in the antioxidant response or the mechanisms impacted by the elevation of ROS such as NLRP3 inflammasome, the polarization of macrophages, and expression or activation of metalloproteinases. This study of the diabetic pro-healing activity of nine plants found in the Caribbean highlights, more particularly, the role of five polyphenolic compounds. At the end of this review, research perspectives are presented.

The Role of MMP-9 and MMP-9 Inhibition in Different Types of Thyroid Carcinoma

Matrix metalloproteinase-9 (MMP-9), one of the most investigated and studied biomarkers of the MMPs family, is a zinc-dependent proteolytic metalloenzyme whose primary function is degrading the extracellular matrix (ECM). It has been proved that MMP-9 expression elevates in multiple pathological conditions, including thyroid carcinoma. MMP-9 has a detectable higher level in malignant or metastatic thyroid tumor tissues than in normal or benign tissues and acts as an additional marker to distinguish different tumor stages because of its close correlations with clinical features, such as lymph node metastasis, TNM stage, tumor size and so on. Natural and non-natural MMP-9 inhibitors suppress its expression, block the progression of diseases, and play a role in therapy consequently. MMP-9 inhibitory molecules also assist in treating thyroid tumors by suppressing the proliferation, invasion, migration, metastasis, viability, adhesion, motility, epithelial-mesenchymal transition (EMT), and other risk factors of different thyroid cancer cells. In a word, discovering and designing MMP-9 inhibitors provide great therapeutic effects and promising clinical values in various types of thyroid carcinoma.

Targeting matrix metalloproteases in diabetic wound healing

Chronic inflammation participates in the progression of multiple chronic diseases, including obesity, diabetes mellitus (DM), and DM related complications. Diabetic ulcer, characterized by chronic wounds that are recalcitrant to healing, is a serious complication of DM tremendously affecting the quality of life of patients and imposing a costly medical burden on society. Matrix metalloproteases (MMPs) are a family of zinc endopeptidases with the capacity of degrading all the components of the extracellular matrix, which play a pivotal part in healing process under various conditions including DM. During diabetic wound healing, the dynamic changes of MMPs in the serum, skin tissues, and wound fluid of patients are in connection with the degree of wound recovery, suggesting that MMPs can function as essential biomarkers for the diagnosis of diabetic ulcer. MMPs participate in various biological processes relevant to diabetic ulcer, such as ECM secretion, granulation tissue configuration, angiogenesis, collagen growth, re-epithelization, inflammatory response, as well as oxidative stress, thus, seeking and developing agents targeting MMPs has emerged as a potential way to treat diabetic ulcer. Natural products especially flavonoids, polysaccharides, alkaloids, polypeptides, and estrogens extracted from herbs, vegetables, as well as animals that have been extensively illustrated to treat diabetic ulcer through targeting MMPs-mediated signaling pathways, are discussed in this review and may contribute to the development of functional foods or drug candidates for diabetic ulcer therapy. This review highlights the regulation of MMPs in diabetic wound healing, and the potential therapeutic ability of natural products for diabetic wound healing by targeting MMPs.

Matrix metalloproteinase profiling and their roles in disease

Matrix metalloproteinases (MMPs) play roles in remodelling of the extracellular matrix that occurs during morphogenesis, repair, and angiogenesis. Dysregulation of extracellular matrix remodelling can lead to cell proliferation, invasion, and tissue fibrosis. Identification of a specific MMP(s) in a disease has been challenging due to the presence of 24 closely-related human MMPs, each existing in three forms, of which only one is active and capable of catalysis. This review focuses on methods for MMP profiling, with particular emphasis on the batimastat affinity resin that binds only to the active forms of MMPs and related ADAMs (a disintegrin and metalloproteinases), which are then identified by mass spectrometry. Use of the batimastat affinity resin has identified targets for intervention in several human diseases.

Mesenchymal Stem Cells Promote Wound Healing and Effects on Expression of Matrix Metalloproteinases-8 and 9 in the Wound Tissue of Diabetic Rats

Diabetic foot ulcer (DFU) is a multifactorial complication of diabetes, mainly manifested as infection, ulcer, or destruction of deep tissue, and there is currently no effective treatment. Several preclinical and clinical studies have proved that the transplantation of mesenchymal stem cells (MSCs) improved wound healing. In this study, we evaluated the therapeutic efficacy of human umbilical cord (hUC-MSCs) in DFU rat model. One dose of hUC-MSCs (1 × 10⁶ cells) was subcutaneously injected around wounds in male Sprague-Dawley rats. Wound healing was evaluated macroscopically (wound closure) every 3 days. In addition, we measured growth factors and specific proteins [matrix metalloproteinases (MMPs)-9 and MMP-8] on Day 14 post hUC-MSC transplantation. Results showed significant differences in the wound healing kinetics of lesions that received hUC-MSCs compared to lesions that received vehicle (phosphate buffered saline; P < 0.05). Enzyme-linked immunosorbent assay analyses indicated that MMP-9 protein contents were significantly upregulated in DFU animals, while MMP-8 was downregulated compared to the diabetic rats (P < 0.05). After MSC treatment, the level of MMP-9 and MMP-8 decreased and increased compared to the vehicle group, respectively. These findings suggest that hUC-MSC transplantation can ameliorate the healing process of DFU rats and a potential mechanism through which MSCs enhance DFU wound healing by decreasing MMP-9 expression and increasing MMP-8 expression. This study represents a promising opportunity to gain insight into how MSCs mediate wound healing.

Polymeric Gel Scaffolds and Biomimetic Environments for Wound Healing

Infected wounds that do not heal are a worldwide problem that is worsening, with more people dying and more money being spent on care. For any disease to be managed effectively, its root cause must be addressed. Effective wound care becomes a bigger problem when various traditional wound healing methods and products may not only fail to promote good healing. Still, it may also hinder the healing process, causing wounds to stay open longer. Progress in tissue regeneration has led to developing three-dimensional scaffolds (3D) or constructs that can be leveraged to facilitate cell growth and regeneration while preventing infection and accelerating wound healing. Tissue regeneration uses natural and fabricated biomaterials that encourage the growth of tissues or organs. Even though the clinical need is urgent, the demand for polymer-based therapeutic techniques for skin tissue abnormalities has grown quickly. Hydrogel scaffolds have become one of the most imperative 3D cross-linked scaffolds for tissue regeneration because they can hold water perfectly and are porous, biocompatible, biodegradable, and biomimetic. For damaged organs or tissues to heal well, the porosity topography of the natural extracellular matrix (ECM) should be imitated. This review details the scaffolds that heal wounds and helps skin tissue to develop. After a brief overview of the bioactive and drug-loaded polymeric hydrogels, the discussion moves on to how the scaffolds are made and what they are made of. It highlights the present uses of in vitro and in-vivo employed biomimetic scaffolds. The prospects of how well bioactiveloaded hydrogels heal wounds and how nanotechnology assists in healing and regeneration have been discussed.

Nicaraven-loaded electrospun wound dressings promote diabetic wound healing via proangiogenic and immunomodulatory functions: a preclinical investigation

The current study developed a biopolymer-based wound dressing by electrospinning of Nicaraven-loaded collagen solution. Firstly, collagen was dissolved in acetic acid, and then Nicaraven was added to the polymeric solution at three different concentrations of 2 w/w%, 4 w/w%, and 6 w/w%. The resulting solution was then electrospun. Various experiments were performed to characterize the produced wound dressings. In vitro studies showed that Nicaraven-loaded scaffolds were not toxic against L929 fibroblast cells and protected them against oxidative stress. Wound healing potential of different formulations of Nicaraven-loaded collagen wound dressings was studied in a rat model of the excisional diabetic wound. The study showed that the collagen/4% Nicaraven and collagen/6% Nicaraven wound dressings exhibited a significantly higher percentage of wound closure, the thickness of the epithelium, and collagen deposition compared with collagen/2% Nicaraven, collagen-only, and sterile gauze groups. Gene expression study showed that the developed wound dressings reduced the tissue expression levels of glutathione peroxidase, NFKβ, and matrix metalloproteinase 9 (MMP9) genes. In addition, in the wounds treated with collagen/4% Nicaraven and collagen/6% Nicaraven scaffolds, wound healing was associated with a higher tissue expression level of b-FGF, VEGF, and collagen type I genes. Overall, wound healing activity of collagen/4% Nicaraven and collagen/6% Nicaraven wound dressings was not significantly different. This study implies that collagen wound dressings incorporated with 4% and 6% Nicaraven can be considered a potential candidate to treat diabetic wounds in the clinic.

Dysregulation of TSP2-Rac1-WAVE2 axis in diabetic cells leads to cytoskeletal disorganization, increased cell stiffness, and dysfunction

Fibroblasts are a major cell population that perform critical functions in the wound healing process. In response to injury, they proliferate and migrate into the wound space, engaging in extracellular matrix (ECM) production, remodeling, and contraction. However, there is limited knowledge of how fibroblast functions are altered in diabetes. To address this gap, several state-of-the-art microscopy techniques were employed to investigate morphology, migration, ECM production, 2D traction, 3D contraction, and cell stiffness. Analysis of cell-derived matrix (CDM) revealed that diabetic fibroblasts produce thickened and less porous ECM that hindered migration of normal fibroblasts. In addition, diabetic fibroblasts were found to lose spindle-like shape, migrate slower, generate less traction force, exert limited 3D contractility, and have increased cell stiffness. These changes were due, in part, to a decreased level of active Rac1 and a lack of co-localization between F-actin and Waskott-Aldrich syndrome protein family verprolin homologous protein 2 (WAVE2). Interestingly, deletion of thrombospondin-2 (TSP2) in diabetic fibroblasts rescued these phenotypes and restored normal levels of active Rac1 and WAVE2-F-actin co-localization. These results provide a comprehensive view of the extent of diabetic fibroblast dysfunction, highlighting the regulatory role of the TSP2-Rac1-WAVE2-actin axis, and describing a new function of TSP2 in regulating cytoskeleton organization.

Recent Advancement of Functional Hydrogels toward Diabetic Wound Management

Wound healing is a dynamic, orchestrated process comprising partially overlapping phases of hemostasis, inflammation, proliferation, and remodeling. This programmed process, dysregulated in diabetic individuals, results in chronic diabetic wounds. The normal process of healing halts at the inflammatory stage, and this prolonged inflammatory phase is characteristic of diabetic wounds. There are a few U.S. Food & Drug Administration approved skin substitutes; dermal matrixes are commercially available to manage diabetic wounds. However, expensiveness and nonresponsiveness in a few instances are the major limitations of such modalities. To address the issues, several treatment strategies have been exploited to treat chronic wounds; among them hydrogel-based systems showed promise due to favorable properties such as excellent absorption capabilities, porous structure, tunable mechanical strength, and biocompatibility. In the past two decades, hydrogels have become one of the most acceptable systems in the field of wound dressing material, offering single functionality to multifunctionality. This review focuses on the advancement of functional hydrogels explored for diabetic wound management. The process of diabetic wound healing is discussed in the light of the normal healing process, and the role of macrophages in the process is explained. This review also discusses the different approaches to treat diabetic wounds using functional hydrogels, along with their future opportunities.

A Review of Immunomodulatory Reprogramming by Probiotics in Combating Chronic and Acute Diabetic Foot Ulcers (DFUs)

Diabetic foot ulcers (DFUs) are characterized by a lack of angiogenesis and distal limb diabetic neuropathy. This makes it possible for opportunistic pathogens to protect the biofilm-encased micro-communities, causing a delay in wound healing. The acute and chronic phases of DFU-associated infections are distinguished by the differential expression of innate proinflammatory cytokines and tumor necrosis factors (TNF-α and -β). Efforts are being made to reduce the microbial bioburden of wounds by using therapies such as debridement, hyperbaric oxygen therapy, shock wave therapy, and empirical antibiotic treatment. However, the constant evolution of pathogens limits the effectiveness of these therapies. In the wound-healing process, continuous homeostasis and remodeling processes by commensal microbes undoubtedly provide a protective barrier against diverse pathogens. Among commensal microbes, probiotics are beneficial microbes that should be administered orally or topically to regulate gut-skin interaction and to activate inflammation and proinflammatory cytokine production. The goal of this review is to bridge the gap between the role of probiotics in managing the innate immune response and the function of proinflammatory mediators in diabetic wound healing. We also highlight probiotic encapsulation or nanoformulations with prebiotics and extracellular vesicles (EVs) as innovative ways to tackle target DFUs.

Glucose and MMP-9 dual-responsive hydrogel with temperature sensitive self-adaptive shape and controlled drug release accelerates diabetic wound healing

Chronic diabetic wounds are an important healthcare challenge. High concentration glucose, high level of matrix metalloproteinase-9 (MMP-9), and long-term inflammation constitute the special wound environment of diabetic wounds. Tissue necrosis aggravates the formation of irregular wounds. All the above factors hinder the healing of chronic diabetic wounds. To solve these issues, a glucose and MMP-9 dual-response temperature-sensitive shape self-adaptive hydrogel (CBP/GMs@Cel&INS) was designed and constructed with polyvinyl alcohol (PVA) and chitosan grafted with phenylboric acid (CS-BA) by encapsulating insulin (INS) and gelatin microspheres containing celecoxib (GMs@Cel). Temperature-sensitive self-adaptive CBP/GMs@Cel&INS provides a new way to balance the fluid-like mobility (self-adapt to deep wounds quickly, approximately 37 °C) and solid-like elasticity (protect wounds against external forces, approximately 25 °C) of self-adaptive hydrogels, while simultaneously releasing insulin and celecoxib on-demand in the environment of high-level glucose and MMP-9. Moreover, CBP/GMs@Cel&INS exhibits remodeling and self-healing properties, enhanced adhesion strength (39.65 ± 6.58 kPa), down-regulates MMP-9, and promotes cell proliferation, migration, and glucose consumption. In diabetic full-thickness skin defect models, CBP/GMs@Cel&INS significantly alleviates inflammation and regulates the local high-level glucose and MMP-9 in the wounds, and promotes wound healing effectively through the synergistic effect of temperature-sensitive shape-adaptive character and the dual-responsive system.

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The hydrogel with temperature-sensitive adaptive shape can fill irregular wounds.

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The hydrogel on-demand releases drugs responding to diabetic wound environment.

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The hydrogel significantly accelerated diabetic wound healing.

Role of matrix metalloproteinases in diabetic foot ulcers: Potential therapeutic targets

Diabetic foot ulcers (DFUs) are pathological states of tissue destruction of the foot or lower extremity in diabetic patients and are one of the serious chronic complications of diabetes mellitus. Matrix metalloproteinases (MMPs) serve crucial roles in both pathogenesis and wound healing. The primary functions of MMPs are degradation, which involves removing the disrupted extracellular matrix (ECM) during the inflammatory phase, facilitating angiogenesis and cell migration during the proliferation phase, and contracting and rebuilding the tissue during the remodeling phase. Overexpression of MMPs is a feature of DFUs. The upregulated MMPs in DFUs can cause excessive tissue degradation and impaired wound healing. Regulation of MMP levels in wounds could promote wound healing in DFUs. In this review, we talk about the roles of MMPs in DFUs and list potential methods to prevent MMPs from behaving in a manner detrimental to wound healing in DFUs.

Platelet-rich plasma promotes diabetic ulcer repair through inhibition of ferroptosis

BACKGROUND

Ferroptosis, a newly discovered form of cell death, can accumulation activates lipid peroxidation and excessive oxidative stress in a high glucose environment. These phenomena suggest there may be ferroptosis pathways in the pathological processes associated with diabetic ulcer (DU). Platelet-rich plasma (PRP) promotes the healing of DU wounds, which may be achieved by the regulation of ferroptosis pathways. Hence, the present study aimed to investigate this association and uncover the potential underlying mechanisms.

METHODS

Cell injury models induced by high glucose were constructed using EA.HY926 (vascular endothelial cells), HSF (fibroblasts), and rat DU models. The MDA, total ROS, total SOD content, the gene and protein expression of GPX4, SLC7A11, and ACSL4, and the expression levels of inflammatory cytokines IL-1β, IL-10, and NLRP3 was subsequently used to evaluate the important role of ferroptosis in the pathological process of DU, and elucidating the molecular mechanism of PRP in ulcer repair.

RESULTS

The results show that compared with the DU control group, the healing rate of the dorsal ulcer wound in the PRP intervention group was accelerated, and the expression levels of inflammatory cytokines IL-1β, IL-10, and NLRP3 in the granulation tissue of ulcer wounds was lower. Further, the expression levels of CD31 and VEGF were higher, the gene and protein expression levels of GPX4 and SLC7A11 were increased, the expression levels of ACSL4 were less, the SOD content was higher, and the MDA content was lower.

CONCLUSIONS

In this study, ferroptosis was preliminarily verified in DUs at the cellular and animal levels, while PRP could inhibit ferroptosis and significantly improve the migration and regeneration ability of fibroblasts and vascular endothelial cells induced by high glucose.

Functionalized Hyaluronic Acid for “In Situ” Matrix Metalloproteinase Inhibition: A Bioactive Material to Treat the Dry Eye Sydrome

Hyaluronic acid (HA) is a naturally occurring polysaccharide with many molecular functions, including maintaining the structure and physiology of the tissues, tissue remodeling, and inflammation. HA is found naturally in physiological tear fluid, possesses excellent mucus-layer-adhesive properties, and is successfully employed in the treatment of dry eye syndrome (DES). However, HA has as major drawback: its rapid in vivo degradation by hyaluronidase. We report on a unique material, namely, HA-3, obtained by the functionalization of HA with the metalloproteinase inhibitor 3 (MMPI). This material is characterized by an increased resistance to hyaluronidase degradation, associated with MMP inhibition properties. The ability of HA-3 to prevent dehydration of human corneal epithelial cells in vitro and in vivo may accelerate the development of more efficient DES treatment and broaden the application of HA in human diseases.

Selective Inhibitors of Medium-Size S1' Pocket Matrix Metalloproteinases: A Stepping Stone of Future Drug Discovery

Among various matrix metalloproteinases (MMPs), MMPs having medium-size S1' pockets are established as promising biomolecular targets for executing crucial roles in cancer, cardiovascular diseases, and neurodegenerative diseases. However, no such MMP inhibitors (MMPIs) are available to date as drug candidates despite a lot of continuous research work for more than three decades. Due to a high degree of structural resemblance among these MMPs, designing selective MMPIs is quite challenging. However, the variability and uniqueness of the S1' pockets of these MMPs make them promising targets for designing selective MMPIs. In this perspective, the overall structural aspects of medium-size S1' pocket MMPs including the unique binding patterns of enzyme-inhibitor interactions have been discussed in detail to acquire knowledge regarding selective inhibitor designing. This overall knowledge will surely be a curtain raiser for the designing of selective MMPIs as drug candidates in the future.

Decreased expression of miR-204-3p in peripheral blood and wound margin tissue associated with the onset and poor wound healing of diabetic foot ulcers

To investigate the relationship between small non-coding RNA-204-3p (miR-204-3p) and the onset and wound healing of diabetic foot ulcers (DFU) and the underlying molecular mechanism, sixty four newly diagnosed patients with T2DM without DFU (T2DM group), 82 T2DM patients with DFU (DFU group), and 60 controls with normal glucose tolerance (NC group) were included. Quantitative real-time PCR (qRT-PCR) method was used to determine miR-204-3p expression levels in peripheral blood and wound margin tissue of subjects, and to analyse the relationship between the expression of miR-204-3p and wound healing. In vitro experiments were also performed to understand the effect of miR-204-3p on high glucose induced injury of HaCaT cells (human keratinocytes). The results showed that miR-204-3p expression level of peripheral blood in the T2DM group was marked lower than that in the NC group [2.38 (1.31-5.04) vs 3.27 (1.51-6.98)] (P < .05). Similarly, the miR-204-3p expression level of peripheral blood in the DFU group was significantly lower than the T2DM group [1.15 (0.78-2.89) vs 2.38 (1.31-5.04)] (P < .01). The expression level of miR-204-3p in peripheral blood and wound margin tissues of DFU patients was positively correlated with the healing rate of foot ulcers after 8 weeks (P < .05). Multifactorial logistic regression analysis showed that decreased expression of miR-204-3p in peripheral blood was an independent risk factor for DFU (OR = 2.95, P < .05). The results of in vitro experiments showed that miR-204-3p could improve the proliferation and migration of HKC cells and reduce the proportion of apoptosis of HKC cells by targeted regulation of zinc finger protein Kruppel like factor 6 (KLF6) in high glucose environment. Therefore, the decreased expression of miR-204-3p in peripheral blood and wound tissue of T2DM patients is closely related to the occurrence and poor wound healing of DFU. The down-regulated expression of miR-204-3p can reduce its ability to antagonise the functional damage of keratinocytes induced by high-glucose conditions. These results will provide potential targets for the treatment of DFU.

Proteomics Identification of Targets for Intervention in Pressure Ulcers

Pressure ulcers (PUs) are chronic wounds that lead to amputations and death. Little is known about why PUs are recalcitrant to healing. Wound healing is mediated by matrix metalloproteinases (MMPs). The 24 MMPs in humans each exist in three forms, of which only one is catalytically competent. We analyzed human PU samples using an affinity resin that exclusively binds to the catalytically competent MMPs. We identified by mass spectrometry the active forms of MMP-1, MMP-8, MMP-9, and MMP-14. Concentrations of MMP-8, MMP-9, and MMP-14 were higher in human PUs compared to the healthy tissue, whereas those for MMP-1 did not change. Decreasing levels of active MMP-9 as the PU improved argued for a detrimental role for this enzyme. In a mouse model of PUs, a highly selective inhibitor for MMP-9 and MMP-14, (R)-ND-336, accelerated wound closure in parallel with significant amelioration of ulcer stage. (R)-ND-336 holds promise as a first-in-class treatment for PUs.

Calendula officinalis Phytochemicals for the Treatment of Wounds Through Matrix Metalloproteinases-8 and 9 (MMP-8 and MMP-9): In Silico Approach

Diabetic foot ulceration is a common complication of an uncontrolled diabetic regimen and is considered a serious type of wound. Matrix metalloprteinases (MMPs) are the common key enzymes in wound management, overexpression of MMPs can lead to chronic wounds and ulcers. Calendula officinalis extract has established its efficacy in treating wounds in folk medicine. In this research work, we will focus on the chemical constituents of this promising herb and will investigate its abilities to target matrix metalloprteinase-8 (MMP-8) and matrix metalloprteinase-9 (MMP-9) proteins through the usage of computer-aided drug design tools. In the current study, several promising dual inhibitors are identified, such as quercetin, isoquercetin, isorhamnetin, and isorhamnetin 3-O glycoside, they showed to be good inhibitors for both enzyme subtypes with greater docking score energies than RND-336, which has been reported as a selective MMP-9 inhibitor. Binding scores and amino acid interactions in addition to molecular dynamics (MD) will be discussed in detail through this research work.

Chronic Inflammation in Non-Healing Skin Wounds and Promising Natural Bioactive Compounds Treatment

Chronic inflammation is one of the hallmarks of chronic wounds and is tightly coupled to immune regulation. The dysregulation of the immune system leads to continuing inflammation and impaired wound healing and, subsequently, to chronic skin wounds. In this review, we discuss the role of the immune system, the involvement of inflammatory mediators and reactive oxygen species, the complication of bacterial infections in chronic wound healing, and the still-underexplored potential of natural bioactive compounds in wound treatment. We focus on natural compounds with antioxidant, anti-inflammatory, and antibacterial activities and their mechanisms of action, as well as on recent wound treatments and therapeutic advancements capitalizing on nanotechnology or new biomaterial platforms.

Identification of Slow-Binding Inhibitors of the BoNT/A Protease

Botulinum neurotoxin A (BoNT/A) is a lethal toxin, which causes botulism, and is categorized as a bioterrorism threat, which causes flaccid paralysis and death. Botulinum A neurotoxicity is governed through its light chain (LC), a zinc metalloprotease. Pharmacological investigations aimed at negating BoNT/A's LC have typically looked to inhibitors that have been shown to inhibit the light chain's activity by reversible zinc chelation within its active site. This report outlines the first examples of nonpeptidic inhibitors of the BoNT/A LC that possess slow-binding kinetics, a needed logic to counteract the longevity of BoNT/A. Cyclopropane, alkyl, and alkenyl derivatives of 2,4-dichlorocinamic hydroxamic acid (DCHA) were shown to possess both one-step and two-step slow-binding kinetics. Structure-kinetic relationships (SKRs) were observed and were rationalized with the aid of docking models that predicted improved interactions with residues within a hydrophobic cleft adjacent to the active site.

Adaptive Gelatin Microspheres Enhanced Stem Cell Delivery and Integration With Diabetic Wounds to Activate Skin Tissue Regeneration

The delayed and complicated diabetic wound healing raises clinical and social concerns. The application of stem cells along with hydrogels is an attractive therapeutic approach. However, low cell retention and integration hindered the performance. Herein, gelatin microspheres were fabricated for local delivery of adipose-derived stem cells (from rats, rADSCs), and the effect of rADSCs with microspheres on diabetic wound healing was examined. Uniform, well-dispersed microspheres were fabricated using the microfluidic technique. Due to geometry differences, the proteinase degradation rate for microspheres was four times that of the bulk hydrogel. The obtained gelatin microspheres supported cell's adhesion and proliferation and provided a suitable microenvironment for rADSC survival. For in vivo animal tests, rADSCs were labeled with CM-Dil for tracking purposes. Microspheres were well embedded in the regenerated tissue and demonstrated good biocompatibility and an adaptive biodegradation rate. Histological examination revealed rADSC-loaded gelatin microspheres that significantly accelerated wound healing via promoting M2 macrophage polarization, collagen deposition, angiogenesis associated with peripheral nerve recovery, and hair follicle formation. Notably, the relative fluorescence intensity around the hair follicle was 17-fold higher than that of the blank group, indicating rADSC participated in the healing process via exosomes. Taken together, the rADSC-laden gelatin microspheres provided a promising strategy for local stem cell delivery to improve diabetic wound healing.

Validating Cell Surface Proteases as Drug Targets for Cancer Therapy: What Do We Know, and Where Do We Go?

Cell surface proteases (also known as ectoproteases) are transmembrane and membrane-bound enzymes involved in various physiological and pathological processes. Several members, most notably dipeptidyl peptidase 4 (DPP4/CD26) and its related family member fibroblast activation protein (FAP), aminopeptidase N (APN/CD13), a disintegrin and metalloprotease 17 (ADAM17/TACE), and matrix metalloproteinases (MMPs) MMP2 and MMP9, are often overexpressed in cancers and have been associated with tumour dysfunction. With multifaceted actions, these ectoproteases have been validated as therapeutic targets for cancer. Numerous inhibitors have been developed to target these enzymes, attempting to control their enzymatic activity. Even though clinical trials with these compounds did not show the expected results in most cases, the field of ectoprotease inhibitors is growing. This review summarizes the current knowledge on this subject and highlights the recent development of more effective and selective drugs targeting ectoproteases among which small molecular weight inhibitors, peptide conjugates, prodrugs, or monoclonal antibodies (mAbs) and derivatives. These promising avenues have the potential to deliver novel therapeutic strategies in the treatment of cancers.

A Review: Matrix Metallopeptidase-9 Nanoparticles Targeted for the Treatment of Diabetic Foot Ulcers

Diabetes foot ulcers are a leading cause of death in diabetic individuals. There are very few medicines and treatments that have received regulatory clearance for this indication, and numerous compounds from various pharmacological classes are now in various stages of clinical studies for diabetic foot ulcers treatment. Multiple risk factors contribute to diabetic foot ulcers, including neuropathy, peripheral artery disease, infection, gender, cigarette smoking, and age. The present difficulties in diabetic foot ulcers treatment are related to bacterial resistance to currently utilized antibiotics. Inhibition of the quorum sensing (QS) system and targeting matrix metallopeptidase-9 (MMP-9) are promising. This study focuses on the difficulties of existing treatment, current treatment technique, and novel pharmacological targets for diabetic foot ulcer. The electronic data base search diabetic for literature on foot ulcers treatment was carried out using Science Direct, PubMed, Google-Scholar, Springer Link, Scopus, and Wiley up to 2021. Becaplermin, a medication that targets MMP-9, glyceryl trinitrate, which inhibits the bacterial quorum sensing system, probiotic therapy, and nano technological solutions are just a few of the novel pharmaceuticals being developed for diabetic foot ulcers treatment. A combination of therapies, rather than one particular agent, will be the best option for treatment of Diabetes foot ulcer since it is multifactorial factors that render occurs of diabetic foot ulcer.

Biomimetic Hydrogels to Promote Wound Healing

Wound healing is a common physiological process which consists of a sequence of molecular and cellular events that occur following the onset of a tissue lesion in order to reconstitute barrier between body and external environment. The inherent properties of hydrogels allow the damaged tissue to heal by supporting a hydrated environment which has long been explored in wound management to aid in autolytic debridement. However, chronic non-healing wounds require added therapeutic features that can be achieved by incorporation of biomolecules and supporting cells to promote faster and better healing outcomes. In recent decades, numerous hydrogels have been developed and modified to match the time scale for distinct stages of wound healing. This review will discuss the effects of various types of hydrogels on wound pathophysiology, as well as the ideal characteristics of hydrogels for wound healing, crosslinking mechanism, fabrication techniques and design considerations of hydrogel engineering. Finally, several challenges related to adopting hydrogels to promote wound healing and future perspectives are discussed.