The Role of Chemokines in Wound Healing

RETRACTED: Healing potential of Spirulina platensis for skin wounds by modulating bFGF, VEGF, TGF-ß1 and α-SMA genes expression targeting angiogenesis and scar tissue formation in the rat model

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief. The journal was alerted to an associated PubPeer post in which suspected duplicated features were identified within Figure 4 B1, and the histological image in Figure 3 A1 appears to have been previously published in another article, as detailed here: https://pubpeer.com/publications/E5658B7B735FF993AA795A5F14C086. The journal performed independent analysis and identified additional suspected image duplications between the images of mice in Figure 1 A+B and images of mice in Figure 6 A+B from Elbialy et al., BMC Veterinary Research (2020). The journal requested the authors provide an explanation to these concerns and associated raw data, but this request was not satisfactorily fulfilled. The Editor-in-Chief assessed the case and decided to retract the article.

Granulation tissue myofibroblasts during normal and pathological skin healing: The interaction between their secretome and the microenvironment

The first role that was proposed for the myofibroblasts located in skin granulation tissue was to contract the edges of the wound in order to reduce the surface to be repaired. This role, linked to the presence of alpha smooth muscle actin, was very quickly confirmed and is part of the definition of granulation tissue myofibroblasts. However, myofibroblasts are cells that also play a much more central role in wound healing. Indeed, it has been shown that these cells produce large quantities of matrix components, and that they stimulate angiogenesis and can recruit immune cells. These actions take place via the secretion of molecules into their environment or indirectly via the production of microvesicles containing pro-fibrotic and pro-angiogenic molecules. Pathologically, granulation tissue can develop into a hypertrophic scar that histologically looks like granulation tissue, but which can remain for months or even years. It has been hypothesized that the myofibroblasts in these tissues remained present instead of disappearing by apoptosis, causing the maintenance of granulation tissue rather than allowing its change into a mature scar. Understanding the roles of both pathological and healthy myofibroblasts in wound tissue is crucial in order to better intervene in the healing mechanism.

Photobiomodulation in diabetic wound healing: A review of red and near-infrared wavelength applications

The development of a painless, non-invasive, and faster way to diabetic wound healing is at the forefront of research. The complexity associated with diabetic wounds makes it a cause for concern amongst diabetic patients and the world at large. Irradiation of cells generates a photobiomodulatory response on cells and tissues, directly causing alteration of cellular processes and inducing diabetic wound repair. Photobiomodulation therapy (PBMT) using red and near-infrared (NIR) wavelengths is being considered as a promising technique for speeding up the rate of diabetic wound healing, eradication of pain and reduction of inflammation through the alteration of diverse cellular and molecular processes. This review presents the extent to which the potential of red and NIR wavelengths have been harnessed in PBMT for diabetic wound healing. Important research challenges and gaps are identified and discussed, and future directions mapped out. This review thus provides useful insights and strategies into improvement of PBMT, including its acceptance within the global medical research community.

Plasmodium infection prevents recurrence and metastasis of hepatocellular carcinoma possibly via inhibition of the epithelial‑mesenchymal transition

Postoperative recurrence causes a high mortality rate among patients with hepatocellular carcinoma (HCC). The current study aimed to determine the effects of Plasmodium infection on HCC metastasis and recurrence. The antitumor effects of Plasmodium infection were determined using two murine orthotopic HCC models: The non-resection model and the resection model. Tumour tissues derived from tumour-bearing mice treated with or without Plasmodium infection were harvested 15 days post-tumour inoculation. The expression levels of biomarkers related to epithelial-mesenchymal transition (EMT) and molecules associated with CC-chemokine receptor 10 (CCR10)-mediated PI3K/Akt/GSK-3β/Snail signalling were identified using reverse transcription-quantitative PCR and western blotting. The results demonstrated that Plasmodium infection significantly suppressed the progression, recurrence and metastasis of HCC in the two mouse models. The expression levels of E-cadherin were significantly higher in the Plasmodium-treated group compared with that in the control group, whereas the expression levels of Vimentin and Snail were significantly lower in the Plasmodium-treated group. Furthermore, Plasmodium infection inhibited the activation of Akt and GSK-3β in the tumour tissues by downregulating the expression levels of CCR10 and subsequently suppressing the accumulation of Snail, which may contribute to the suppression of EMT and the prevention of tumour recurrence and metastasis. In conclusion, the results of the present study demonstrated that Plasmodium infection inhibited the recurrence and metastasis and improved the prognosis of HCC by suppressing CCR10-mediated PI3K/Akt/GSK-3β/Snail signalling and preventing the EMT. These results may be important for the development of novel therapies for HCC recurrence and metastasis, especially for patients in the perioperative period.

A cut above the rest: oxidative stress in chronic wounds and the potential role of polyphenols as therapeutics

OBJECTIVES

The pathophysiology of chronic wounds typically involves redox imbalance and inflammation pathway dysregulation, often with concomitant microbial infection. Endogenous antioxidants such as glutathione and tocopherols are notably reduced or absent, indicative of significant oxidative imbalance. However, emerging evidence suggests that polyphenols could be effective agents for the amelioration of this condition. This review aims to summarise the current state of knowledge surrounding redox imbalance in the chronic wound environment and the potential use of polyphenols for the treatment of chronic wounds.

KEY FINDINGS

Polyphenols provide a multi-faceted approach towards the treatment of chronic wounds. Firstly, their antioxidant activity allows direct neutralisation of harmful free radicals and reactive oxygen species, assisting in restoring redox balance. Upregulation of pro-healing and anti-inflammatory gene pathways and enzymes by specific polyphenols further acts to reduce redox imbalance and promote wound healing actions, such as proliferation, extracellular matrix deposition and tissue remodelling. Finally, many polyphenols possess antimicrobial activity, which can be beneficial for preventing or resolving infection of the wound site.

SUMMARY

Exploration of this diverse group of natural compounds may yield effective and economical options for the prevention or treatment of chronic wounds.

Serum levels of CC chemokine ligands in cutaneous leishmaniasis patients

The crucial functions of chemokine/receptors in numerous parasitic infections, including leishmaniasis, are well documented. This study aimed to assess the serum levels of CC ligand (CCL) 2, CCL5, and CCL11 in cutaneous leishmaniasis (CL) patients. 64 patients, suffering from CL and 100 healthy people were selected, and their blood serum concentrations of CCL2, CCL5, and CCL11 were measured using enzyme-linked immunosorbent assay. The results demonstrated that while the mean serum levels of CCL5 and CCL11 increased significantly in CL patients, the mean serum levels of CCL2 decreased, compared to the control group. Despite the sufficient production of CCL5 and CCL11 in CL patients, they suffered from CCL2 deficiency, as the defense mechanism against parasitic infection. These findings suggest a mechanism that might partially explain the patients' susceptibility to persistent infection and their inability to clear the parasites.

Development of stabilized dual growth factor-loaded hyaluronate collagen dressing matrix

Patients with diabetes experience impaired growth factor production such as epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF), and they are reportedly involved in wound healing processes. Here, we report dual growth factor-loaded hyaluronate collagen dressing (Dual-HCD) matrix, using different ratios of the concentration of stabilized growth factors—stabilized-EGF (S-EGF) and stabilized-bFGF (S-bFGF). At first, the optimal concentration ratio of S-EGF to S-bFGF in the Dual-HCD matrix is determined to be 1:2 in type I diabetic mice. This Dual-HCD matrix does not cause cytotoxicity and can be used in vivo. The wound-healing effect of this matrix is confirmed in type II diabetic mice. Dual HCD enhances angiogenesis which promotes wound healing and thus, it shows a significantly greater synergistic effect than the HCD matrix loaded with a single growth factor. Overall, we conclude that the Dual-HCD matrix represents an effective therapeutic agent for impaired diabetic wound healing.

Chronic Diabetic Wounds and Their Treatment with Skin Substitutes

With the global prevalence of type 2 diabetes mellitus steeply rising, instances of chronic, hard-healing, or non-healing diabetic wounds and ulcers are predicted to increase. The growing understanding of healing and regenerative mechanisms has elucidated critical regulators of this process, including key cellular and humoral components. Despite this, the management and successful treatment of diabetic wounds represents a significant therapeutic challenge. To this end, the development of novel therapies and biological dressings has gained increased interest. Here we review key differences between normal and chronic non-healing diabetic wounds, and elaborate on recent advances in wound healing treatments with a particular focus on biological dressings and their effect on key wound healing pathways.

Chemokine Profiles Are Affected in Serum of Patients with Acute Rejection of Kidney Allograft

Kidney allograft transplantation improved the prognosis and quality of life of patients with end-stage renal diseases but the occurrence of acute rejection represents a limitation of the final outcome. Noninvasive biomarkers are needed as well as further advancements in the understanding of immune mechanisms of reaction to the allograft. Our study of 138 patients focused on one-year monitoring of serum concentrations of 12 chemokines regulating the recruitment of different immune cells into transplanted allograft and on in vitro regulation of the same chemokines release by interactions of renal proximal epithelial cells with monocyte/macrophage cell line stimulated with TNF alpha. In a group of 44 patients with acute rejection, higher serum pretransplant levels of CXCL1, CXCL5, CXCL6, CCL2, CCL21, and particularly CXCL10 and CX3CL1(both p < 0.001) were found suggesting their higher proinflammatory status as compared to subjects with the uncomplicated outcome. In samples collected at the day of biopsy positive for acute rejection, chemokines CXCL9 and CXCL11 attracting preferentially Th1 lymphocytes were found to be upregulated. In our in vitro model with TNF alpha induction, renal proximal epithelial cells seemed to be a more potent source of chemokines attracting neutrophils as compared to monocyte/macrophage cell line but the coculture of these cells potentiated release of neutrophilic chemokines CXCL5 and CXCL6. Similar augmentation of chemokine production was found also in the case of CCL2. On the other hand, adding of monocytes/macrophages to a culture of renal epithelial cells suppressed the release of CXCL10 and CXCL11 attracting T lymphocytes. We assume from our data that in kidney allograft transplantation, chemokines attracting neutrophils, T lymphocytes, and monocytes are induced simultaneously and measurement some of them in combination might be used as biomarkers of acute rejection. Mutual cell-cell interactions of immune cells with renal parenchyma seem to be important for fine regulation of chemokine release.

Chemokines as the critical factors during bladder cancer progression: an overview

Bladder cancer (BCa) is one of the most frequent urogenital malignancies which is mainly observed among men. There are various genetic and environmental risk factors associated with BCa progression. Transurethral endoscopic resection and open ablative surgery are the main treatment options for muscle invasive BCa. BCG therapy is also employed following the endoscopic resection to prevent tumor relapse. The tumor microenvironment is the main interaction site of tumor cells and immune system in which the immune cells are recruited via chemokines and chemokine receptors. In present review we summarized the main chemokines and chemokine receptors which have been associated with histopathological features of BCa patients in the world. This review highlights the chemokines and chemokine receptors as critical markers in early detection and therapeutic purposes among BCa patients and clarifies their molecular functions during BCa progression and metastasis.

Dermal Drivers of Injury-Induced Inflammation: Contribution of Adipocytes and Fibroblasts

Irregular inflammatory responses are a major contributor to tissue dysfunction and inefficient repair. Skin has proven to be a powerful model to study mechanisms that regulate inflammation. In particular, skin wound healing is dependent on a rapid, robust immune response and subsequent dampening of inflammatory signaling. While injury-induced inflammation has historically been attributed to keratinocytes and immune cells, a vast body of evidence supports the ability of non-immune cells to coordinate inflammation in numerous tissues and diseases. In this review, we concentrate on the active participation of tissue-resident adipocytes and fibroblasts in pro-inflammatory signaling after injury, and how altered cellular communication from these cells can contribute to irregular inflammation associated with aberrant wound healing. Furthering our understanding of how tissue-resident mesenchymal cells contribute to inflammation will likely reveal new targets that can be manipulated to regulate inflammation and repair.

Effects of Hsian-tsao (Mesona procumbens Hemsl.) extracts and its polysaccharides on the promotion of wound healing under diabetes-like conditions

Hsian-tsao extracts and its polysaccharides accelerate wound healing in cell models and diabetic mice.

Knockout of sodium channel Nax delays re-epithelializathion of splinted murine excisional wounds

Mammalian wound healing is a carefully orchestrated process in which many cellular and molecular effectors respond in concert to perturbed tissue homeostasis in order to close the wound and re-establish the skin barrier. The roles of many of these molecular effectors, however, are not entirely understood. Our lab previously demonstrated that the atypical sodium channel Na_x (encoded by Scn7a) responds to wound-induced epidermal dehydration, resulting in molecular cascades that drive pro-inflammatory signaling. Acute inhibition of Na_x was sufficient to attenuate dermatopathological symptoms in models of hypertrophic scar and dermatitis. To date, however, the role of Na_x in excisional wound healing has not been demonstrated. Here we report development of a knockout mouse that lacks expression of functional Na_x , and we demonstrate that lack of functional Na_x results in deficient wound healing in a murine splinted excisional wound healing model. This deficiency in wound healing was reflected in impaired re-epithelialization and decreased keratinocyte proliferation, a finding which was further supported by decreased proliferation upon Na_x knockdown in HaCaT cells in vitro. Defective wound healing was observed alongside increased expression of inflammatory genes in the wound epidermis of Na_x ^-/- mice, suggesting that mice lacking functional Na_x retain the ability to undergo skin inflammation. Our observations here motivate further investigation into the roles of Na_x in wound healing and other skin processes.

Stem cell recruitment based on scaffold features for bone tissue engineering

Stem-cell based therapy strategies are promising approaches for the treatment of bone defects. However, extensive cell expansion steps, the low rate of cell survival and uncontrolled differentiation of stem cells transplanted into the body currently remain key challenges in advancing stem cell therapeutics. An alternative strategy is to use specifically designed bone scaffolds to recruit endogenous stem cells upon implantation and to stimulate new bone formation and remodeling. Stem cell recruitment based on scaffold features for bone tissue engineering relies on the development of scaffolds that can effectively mobilize and recruit endogenous stem cells to the implantation site. This article addresses the recent advances in the recruitment of endogenous stem cells in applications of bone scaffolds, particularly focusing on chemical modification and physical characteristic modification of the scaffold for endogenous stem cell homing and recruitment. Finally, the continuing challenges and future directions of scaffold-based stem cell recruitment are discussed.

Anti-Ageing Protein β-Klotho Rejuvenates Diabetic Stem Cells for Improved Gene-Activated Scaffold Based Wound Healing

Skin wounds can lead to serious morbidity complications in diabetic patients due to the reduced healing potential of autologous stem cells. One reason for the low functional potency of stem cells from diabetic patients (diabetic stem cells) is attributed to their senescent-like nature. Here, we investigated if an anti-ageing protein, β-klotho, could be used to rejuvenate diabetic stem cells and to promote pro-angiogenic gene-activated scaffold (GAS)-induced functional response for wound healing applications. Human stem cells derived from the adipose tissue (adipose-derived stem cells (ADSCs)) of normal and diabetic (type 2) donors were used for the study. We report that the β-klotho priming facilitated inflammatory signal pruning by reducing interleukin-8 release by more than half while concurrently doubling the release of monocyte chemoattractant protein-1. Additionally, β-klotho priming enhanced the pro-angiogenic response of diabetic ADSCs on GAS by dampening the release of anti-angiogenic factors (i.e., pigment epithelium-derived factor, tissue inhibitor of metalloproteinase-1 and thrombospondin-1) while simultaneously supporting the expression of pro-angiogenic factors (i.e., Vascular Endothelial Growth Factor (VEGF), angiopoietin-2 and angiogenin). Finally, we show that β-klotho pre-treatment expedites the cellular expression of matrix proteins such as collagen IV and collagen VI, which are implicated in tissue maturation. Taken together, our study provides evidence that the synergistic effect of the pro-angiogenic GAS and β-klotho activation effectively accelerates the functional development of diabetic ADSCs for wound healing applications.

Enhanced Proliferation of Ly6C+ Monocytes/Macrophages Contributes to Chronic Inflammation in Skin Wounds of Diabetic Mice

Diabetic wounds are characterized by persistent accumulation of proinflammatory monocytes (Mo)/macrophages (MΦ) and impaired healing. However, the mechanisms underlying the persistent accumulation of Mo/MΦ remain poorly understood. In this study, we report that Ly6C⁺F4/80^lo/- Mo/MΦ proliferate at higher rates in wounds of diabetic mice compared with nondiabetic mice, leading to greater accumulation of these cells. Unbiased single cell RNA sequencing analysis of combined nondiabetic and diabetic wound Mo/MΦ revealed a cluster, populated primarily by cells from diabetic wounds, for which genes associated with the cell cycle were enriched. In a screen of potential regulators, CCL2 levels were increased in wounds of diabetic mice, and subsequent experiments showed that local CCL2 treatment increased Ly6C⁺F4/80^lo/- Mo/MΦ proliferation. Importantly, adoptive transfer of mixtures of CCR2^-/- and CCR2^+/+ Ly6C^hi Mo indicated that CCL2/CCR2 signaling is required for their proliferation in the wound environment. Together, these data demonstrate a novel role for the CCL2/CCR2 signaling pathway in promoting skin Mo/MΦ proliferation, contributing to persistent accumulation of Mo/MΦ and impaired healing in diabetic mice.

Adipose stem cell secretion combined with biomaterials facilitates large-area wound healing

Adipose-derived stem cell (ADSC)-based therapeutic strategies are in fast-pace advancement in wound treatment due to their availability and the ability to self-renew, undergo multilineage differentiation and self-renewal. Existing studies have successfully explored ADSCs to facilitate scar-free healing of small wounds, but whether the healing of large-area wounds that exhibit over 50% of skin tissue loss in the entire body could be achieved remains controversial. This study sought to review the mechanism of physiological wound healing, and discuss the roles played by chemokines, biological factors and biomaterial scaffolds. The possibility of applying ADSC-conditioned medium or ADSC-released exosomes as 'off-the-shelf' tissue engineering products, integrated with biomaterial scaffolds to facilitate wound healing, was analyzed.

Pro-inflammatory effect of obesity on rats with burn wounds

Objective

A burn is an inflammatory injury to the skin or other tissue due to contact with thermal, radioactive, electric, or chemical agents. Burn injury is an important cause of disability and death worldwide. Obesity is a significant public health problem, often causing underlying systemic inflammation. Studying the combined impact of burn injuries on obese patients has become critical to the successful treatment of these patients. The aim of this paper is to highlight the effect of inflammation associated with burn injuries on several body weight group in a rat study.

Materials and methods

Different degrees of obesity and burns were established in rats and divided into a normal weight group, overweight group, obese group, second-degree burn group, third-degree burn group, over-weight second-degree burn group, over-weight third-degree burn group, obese second-degree burn group, and obese third-degree burn group (20 rats per group). Changes in inflammatory factors and growth factor were measured on the 1st, 3rd, 7th and 14th days after burns were inflicted.

Results

The ELISA test showed that in the unburned control group, MCP-1, IL-1β and TNF-α protein expressions in the obese and over-weight groups were higher than the normal-weight group (P < 0.05). RT-PCR test showed that the expressions of MCP-1, IL-1β and TNF-α genes in the obese group were higher compared to the overweight and normal weight groups (P < 0.05). Three and 7 days after burns were inflicted, the level of VEGF in the normal weight group was higher than the obese group (P < 0.05), however increased VEGF was not observed on days 1 and 14.

Conclusion

Burn injury and obesity have a mutually synergistic effect on the body’s inflammatory response.

Candidate rejuvenating factor GDF11 and tissue fibrosis: friend or foe?

Growth differentiation factor 11 (GDF11 or bone morphogenetic protein 11, BMP11) belongs to the transforming growth factor-β superfamily and is closely related to other family member-myostatin (also known as GDF8). GDF11 was firstly identified in 2004 due to its ability to rejuvenate the function of multiple organs in old mice. However, in the past few years, the heralded rejuvenating effects of GDF11 have been seriously questioned by many studies that do not support the idea that restoring levels of GDF11 in aging improves overall organ structure and function. Moreover, with increasing controversies, several other studies described the involvement of GDF11 in fibrotic processes in various organ setups. This review paper focuses on the GDF11 and its pro- or anti-fibrotic actions in major organs and tissues, with the goal to summarize our knowledge on its emerging role in regulating the progression of fibrosis in different pathological conditions, and to guide upcoming research efforts.

Effects of Rutin on Wound Healing in Hyperglycemic Rats

Long-term poor glycemic control negatively affects macrovascular and microvascular diseases, as well as wound restoration. Buckwheat is a good source of rutin (quercetin-3-O-rutoside) and has benefits in regulating blood sugar. This study was to evaluate the antioxidant and anti-inflammatory effects of rutin on wound healing in streptozotocin-induced hyperglycemic rats. Eighteen male Wistar rats were randomly divided into three groups: normal (NDM), hyperglycemic (DM), and hyperglycemic with rutin (DMR). After induction of hyperglycemia for 2 days, a 15 × 15 mm wound was induced on the back of each rat. Intraperitoneal injection of rutin significantly ameliorated diabetes-induced body weight loss and improved metabolic dysfunctions of hyperglycemic rats. Based on appearance and histopathological staining, rutin promotes wound healing and inhibits production of inflammatory cells. The immunoblotting data indicated that rutin promotes production of antioxidant enzymes induced by nuclear factor erythroid 2-related factor 2 (NRF2), inhibits the expression of matrix metalloproteinases (MMPs) regulated by NF-κB, and decreases the expression of vascular endothelial growth factor (VEGF). It also promotes the expression of neurogenic-related protein (UCH-L1). The aforementioned results indicated that rutin reduces oxidative stress and inflammatory response in hyperglycemic rats, promoting wound healing and subsequently reducing the risk of wound ulcers.

Eicosanoids in Skin Wound Healing

Wound healing is an important process in the human body to protect against external threats. A dysregulation at any stage of the wound healing process may result in the development of various intractable ulcers or excessive scar formation. Numerous factors such as growth factors, cytokines, and chemokines are involved in this process and play vital roles in tissue repair. Moreover, recent studies have demonstrated that lipid mediators derived from membrane fatty acids are also involved in the process of wound healing. Among these lipid mediators, we focus on eicosanoids such as prostaglandins, thromboxane, leukotrienes, and specialized pro-resolving mediators, which are produced during wound healing processes and play versatile roles in the process. This review article highlights the roles of eicosanoids on skin wound healing, especially focusing on the biosynthetic pathways and biological functions, i.e., inflammation, proliferation, migration, angiogenesis, remodeling, and scarring.

Effects of whole-body cryotherapy on the innate and adaptive immune response in cyclists and runners

The study aimed to identify the effects of whole-body cryotherapy (WBC) on immunological, hormonal, and metabolic responses of non-professional male athletes. Ten cyclists and ten middle-distance runners received 3 once-a-day sessions of WBC. Before initiating and after the final WBC session, a full set of hematologic parameters, serum chemistry profile, hormones, circulating mitochondrial (mt) DNA levels, cytokines, and chemokines concentration were evaluated. The phenotype of monocyte, T cells, and B cells was analyzed. mRNA expression of 6 genes involved in inflammasome activation (NAIP, AIM2, NLRP3, PYCARD, IL-1β, and IL-18) was quantified. WBC reduced glucose and C and S protein and increased HDL, urea, insulin-like growth factor (IGF)-1, follicle-stimulating hormone, IL-18, IL-1RA, CCL2, and CXCL8. Intermediate and non-classical monocyte percentages decreased, and the CD14, CCR5, CCR2, and CXCR4 expressions changed in different subsets. Only IL-1β mRNA increased in monocytes. Finally, a redistribution of B and T cell subsets was observed, suggesting the migration of mature cells to tissue. WBC seems to induce changes in both innate and adaptive branches of the immune system, hormones, and metabolic status in non-professional male athletes, suggesting a beneficial involvement of WBC in tissue repair.

The Effect of Inflammation on the Healing Process of Acute Skin Wounds Under the Treatment of Wounds with Injections in Rats

PURPOSE

To study the effects of inflammation on the healing process of rats' acute skin wounds during treatment with different injections.

METHODS

The study was carried out on Wistar rats, on which square wounds were simulated in the back region. Four groups of wounds were studied. On the day of the simulation (day 0), solutions of the drugs were injected into the wounds: an isotonic sodium chloride solution (Control group), mesenchymal stem cells (SC group), collagen (Collagen group), and a deproteinized hemoderivative of calf blood (DHB group). Within 2 weeks, the wound healing process was assessed by observing and calculating changes in the wound areas, temperatures, and epithelialization levels. On days 3, 7, and 14, wound tissue samples were taken for histological examination, morphological analysis of the healing process, and quantitative assessment of granulation layers' leukocyte infiltration.

RESULTS

A correlation between the process of inflammation and epithelization during the healing of skin wounds was established. The anti-inflammatory effect of SC injection on the wound edge tissues was determined, as well as the pro-inflammatory effect of DHB, and the absence of effects on the inflammation course under the collagen treatment. Compared to the control group, the transition from the exudative phase of inflammation to the proliferative phase was faster, as well was wound epithelialization in the SC and Collagen groups. A negative correlation between the level of tissue temperature in the center of wounds and their area were recorded, which intensified over time.

CONCLUSION

The severity and duration of the inflammation process during wound healing were ambiguous with the use of different injection treatments. This should compel clinicians to use different markers of drug therapy effectiveness during wound healing. Excessive leukocyte infiltration with a low temperature of wounds and a large scab were markers of delayed wound healing.

Notch1 signaling determines the plasticity and function of fibroblasts in diabetic wounds

Fibroblasts play a pivotal role in wound healing. However, the molecular mechanisms determining the reparative response of fibroblasts remain unknown. Here, we identify Notch1 signaling as a molecular determinant controlling the plasticity and function of fibroblasts in modulating wound healing and angiogenesis. The Notch pathway is activated in fibroblasts of diabetic wounds but not in normal skin and non-diabetic wounds. Consistently, wound healing in the FSP-1 ^+/- ;ROSA ^LSL-N1IC+/+ mouse, in which Notch1 is activated in fibroblasts, is delayed. Increased Notch1 activity in fibroblasts suppressed their growth, migration, and differentiation into myofibroblasts. Accordingly, significantly fewer myofibroblasts and less collagen were present in granulation tissues of the FSP-1 ^+/- ;ROSA ^LSL-N1IC+/+ mice, demonstrating that high Notch1 activity inhibits fibroblast differentiation. High Notch1 activity in fibroblasts diminished their role in modulating the angiogenic response. We also identified that IL-6 is a functional Notch1 target and involved in regulating angiogenesis. These findings suggest that Notch1 signaling determines the plasticity and function of fibroblasts in wound healing and angiogenesis, unveiling intracellular Notch1 signaling in fibroblasts as potential target for therapeutic intervention in diabetic wound healing.

Recombinant Myxoma Virus-Derived Immune Modulator M-T7 Accelerates Cutaneous Wound Healing and Improves Tissue Remodeling

Complex dermal wounds represent major medical and financial burdens, especially in the context of comorbidities such as diabetes, infection and advanced age. New approaches to accelerate and improve, or "fine tune" the healing process, so as to improve the quality of cutaneous wound healing and management, are the focus of intense investigation. Here, we investigate the topical application of a recombinant immune modulating protein which inhibits the interactions of chemokines with glycosaminoglycans, reducing damaging or excess inflammation responses in a splinted full-thickness excisional wound model in mice. M-T7 is a 37 kDa-secreted, virus-derived glycoprotein that has demonstrated therapeutic efficacy in numerous animal models of inflammatory immunopathology. Topical treatment with recombinant M-T7 significantly accelerated wound healing when compared to saline treatment alone. Healed wounds exhibited properties of improved tissue remodeling, as determined by collagen maturation. M-T7 treatment accelerated the rate of peri-wound angiogenesis in the healing wounds with increased levels of TNF, VEGF and CD31. The immune cell response after M-T7 treatment was associated with a retention of CCL2 levels, and increased abundances of arginase-1-expressing M2 macrophages and CD4 T cells. Thus, topical treatment with recombinant M-T7 promotes a pro-resolution environment in healing wounds, and has potential as a novel treatment approach for cutaneous tissue repair.

Health Benefits of Silybum marianum: Phytochemistry, Pharmacology, and Applications

Silybum marianum (SM), a well-known plant used as both a medicine and a food, has been widely used to treat various diseases, especially hepatic diseases. The seeds and fruits of SM contain a flavonolignan complex called silymarin, the active compounds of which include silybin, isosilybin, silychristin, dihydrosilybin, silydianin, and so on. In this review, we thoroughly summarize high-quality publications related to the pharmacological effects and underlying mechanisms of SM. SM has antimicrobial, anticancer, hepatoprotective, cardiovascular-protective, neuroprotective, skin-protective, antidiabetic, and other effects. Importantly, SM also counteracts the toxicities of antibiotics, metals, and pesticides. The diverse pharmacological activities of SM provide scientific evidence supporting its use in both humans and animals. Multiple signaling pathways associated with oxidative stress and inflammation are the common molecular targets of SM. Moreover, the flavonolignans of SM are potential agonists of PPARγ and ABCA1, PTP1B inhibitors, and metal chelators. At the end of the review, the potential and perspectives of SM are discussed, and these insights are expected to facilitate the application of SM and the discovery and development of new drugs. We conclude that SM is an interesting dietary medicine for health enhancement and drug discovery and warrants further investigation.

Tissue-Specific Role of Macrophages in Noninfectious Inflammatory Disorders

Chronic inflammation may not begin with local tissue disorders, such as hypoxia, but with the accumulation of critically activated macrophages in one site. The purpose of this review is to analyze the data reported in the scientific literature on the features of the functions of macrophages and their contributions to the development of pathology in various tissues during aseptic inflammation in obese subjects. In individuals with obesity, increased migration of monocytes from the peripheral blood to various tissues, the proliferation of resident macrophages and a change in the balance between alternatively activated anti-inflammatory macrophages (M2) and pro-inflammatory classically activated macrophages (M1) towards the latter have been observed. The primary cause of some metabolic pathologies has been precisely identified as the recruitment of macrophages with an altered phenotype, which is probably typical for many other pathologies. Recent studies have identified phenotypes, such as metabolically activated M (MMe), oxidized (Mox), hemoglobin-related macrophages (Mhem and MHb), M4 and neuroimmunological macrophages (NAM, SAM), which directly and indirectly affect energy metabolism. The high heterogeneity of macrophages in tissues contributes to the involvement of these cells in the development of a wide range of immune responses, including pathological ones. The replenishment of tissue-specific macrophages occurs at the expense of infiltrating monocyte-derived macrophages (MoMFs) in the pathological process. The origin of MoMFs from a general precursor retains their common regulatory mechanisms and similar sensitivity to regulatory stimuli. This makes it possible to find universal approaches to the effect on these cells and, as a consequence, universal approaches for the treatment of various pathological conditions.

The Immune Nature of Platelets Revisited

Platelets are the primary cellular mediators of hemostasis and this function firmly acquaints them with a variety of inflammatory processes. For example, platelets can act as circulating sentinels by expressing Toll-like receptors (TLR) that bind pathogens and this allows platelets to effectively kill them or present them to cells of the immune system. Furthermore, activated platelets secrete and express many pro- and anti-inflammatory molecules that attract and capture circulating leukocytes and direct them to inflamed tissues. In addition, platelets can directly influence adaptive immune responses via secretion of, for example, CD40 and CD40L molecules. Platelets are also the source of most of the microvesicles in the circulation and these miniscule elements further enhance the platelet’s ability to communicate with the immune system. More recently, it has been demonstrated that platelets and their parent cells, the megakaryocytes (MK), can also uptake, process and present both foreign and self-antigens to CD8+ T-cells conferring on them the ability to directly alter adaptive immune responses. This review will highlight several of the non-hemostatic attributes of platelets that clearly and rightfully place them as integral players in immune reactions.

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Platelets can act as circulating sentinels by expressing pathogen-associated molecular pattern receptors that bind pathogens and induce their killing and elimination.

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Activated platelets secrete and express a multitude of pro- and anti-inflammatory molecules that attract and capture circulating leukocytes and direct them to inflamed tissues.

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Platelets express and secrete many critical immunoregulatory molecules that significantly affect both innate and adaptive immune responses.

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Platelets are the primary source of microparticles in the circulation and these augment the platelet’s ability to communicate with the immune system.

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Platelets and megakaryocytes can act as antigen presenting cells and present both foreign- and self-peptides to T-cells.

Challenges and New Therapeutic Approaches in the Management of Chronic Wounds

Chronic non-healing wounds are estimated to cost the US healthcare $28-$31 billion per year. Diabetic ulcers, arterial and venous ulcers, and pressure ulcers are some of the most common types of chronic wounds. The burden of chronic wounds continues to rise due to the current epidemic of obesity and diabetes and the increase in elderly adults in the population who are more vulnerable to chronic wounds than younger individuals. This patient population is also highly vulnerable to debilitating infections caused by opportunistic and multi-drug resistant pathogens. Reduced microcirculation, decreased availability of cytokines and growth factors that promote wound closure and healing, and infections by multi-drug resistant and biofilm forming microbes are some of the critical factors that contribute to the development of chronic non-healing wounds. This review discusses novel approaches to understand chronic wound pathology and methods to improve chronic wound care, particularly when chronic wounds are infected by multi-drug resistant, biofilm forming microbes.

Deciphering the secretome of leukocyte-platelet rich fibrin: towards a better understanding of its wound healing properties

Leukocyte-platelet rich fibrin (L-PRF) is extensively used in the dentistry field and other clinical scenarios due to its regeneration properties. The goal of the present study was to depict the L-PRF secretome and how it changes over time. We obtained L-PRF membranes and cultured them in DMEM. The secretome was collected at days 3, 7 and 21. The secretome at day 3 was analysed by LC–MS/MS and differences over time were analysed by Sequential Window Acquisition of all Theoretical Mass Spectra (SWATH). Overall, 705 proteins were identified in the secretome of L-PRF membranes after 3 days of culture, including growth factors (EGF, PDGFA) and proteins related to platelet and neutrophil degranulation. A total of 202 differentially secreted proteins were quantified by SWATH when comparing secretomes at days 3, 7 and 21. Most of them were enriched at day 3 such as MMP9, TSP1 and CO3. On the contrary, fibrinogen and CATS were found down-regulated at day 3. Growth factor and western blotting analysis corroborated the proteomic results. This is the most detailed proteome analysis of the L-PRF secretome to date. Proteins and growth factors identified, and their kinetics, provide novel information to further understand the wound healing properties of L-PRF.

Role of Nrf2 in MALAT1/ HIF-1α loop on the regulation of angiogenesis in diabetic foot ulcer

Diabetic non healing wounds often result in significant morbidity and mortality. The number of effective targets to detect these wounds are meagre. Slow lymphangiogenesis is one of the complex processes involved in impaired healing of wounds. Long non coding RNAs (lncRNAs) have been importantly recognized for their role in pathological conditions. Multiple studies highlighting the role of lncRNAs in the regulation of several biological processes and complex diseases. Herein, we investigated the role of lncRNA Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in the progression of diabetic foot ulcer (DFU). We report a significant reduction in the expression of lncRNA MALAT1 in the infected DFU subjects which was positively correlated with the expression of angiogenic factors such as Nrf2, HIF-1α and VEGF. Further, expression of pro-inflammatory markers TNF-α and IL-6 were found to be increased while, the expression of anti-inflammatory marker IL-10 was decreased in infected DFU tissues. Involvement of lncRNA MALAT1 in angiogenesis in EA.hy926 cells was demonstrated by silencing the expression of Nrf2, HIF-1α, and VEGF through interference mediated by MALAT1. In addition, its inflammatory role was demonstrated by decreased expression of TNF-α, IL-6 and not affecting the expression of IL-10. Further, CRISPR-Cas9 knock out of Nrf2 decreased the expression of lncRNA MALAT1, HIF-1α and VEGF which revealed the association of Nrf2 in regulating MALAT1/HIF-1α loop through positive feedback mechanism. Collectively, our results suggested the role of Nrf2 on MALAT1/HIF-1α loop in the regulation of angiogenesis, which could act as a novel target in the treatment of diabetic wounds.

New Scheme of Intermittent Benznidazole Administration in Patients Chronically Infected with Trypanosoma cruzi: Clinical, Parasitological, and Serological Assessment after Three Years of Follow-Up

In a pilot study, we showed that the intermittent administration of benznidazole in chronic Chagas disease patients resulted in a low rate of treatment suspension and therapeutic failure, as assessed by quantitative PCR (qPCR) at the end of treatment. Here, a 3-year posttreatment follow-up study of the same cohort of patients is presented. The treatment scheme consisted of 12 doses of benznidazole at 5 mg/kg of body weight/day in two daily doses every 5 days. Parasite load, Trypanosoma cruzi-specific antibodies, and serum chemokine levels were measured prior to treatment and after a median follow-up of 36 months posttreatment by DNA minicircle kinetoplastid and nuclear DNA satellite sequence qPCR methods, conventional serological techniques, a Luminex-based assay with recombinant T. cruzi proteins, and a cytometric bead array. At the end of follow-up, 14 of 17 (82%) patients had negative qPCR findings, whereas three of 17 (18%) had detectable nonquantifiable findings by at least one of the qPCR techniques. A decline in parasite-specific antibodies at 12 months posttreatment was confirmed by conventional serological tests and the Luminex assays. Monocyte chemoattractant protein 1 levels increased after treatment, whereas monokine induced by gamma interferon levels decreased. New posttreatment electrocardiographic abnormalities were observed in only one patient who had cardiomyopathy prior to treatment. Together, these data strengthen our previous findings by showing that the intermittent administration of benznidazole results in a low rate of treatment suspension, with treatment efficacy comparable to that of a daily dose of 5 mg/kg for 60 days.

Exosomes derived from TSG-6 modified mesenchymal stromal cells attenuate scar formation during wound healing

Mesenchymal stromal cell (MSC)-derived exosome therapy has emerged as an effective therapy strategy for the pathological scar formation. However, the underlying mechanisms have not been completely understood. In the current study, we investigate the therapeutic effect of TSG-6 modified MSC-derived exosomes on a mouse full-thickness wound model and provide evidence of a possible mechanism for MSC-derived exosomes to prevent from scar formation. Overexpression and knockdown of TSG-6 were conducted by lentivirus infection into hBMSCs. Exosomes were isolated from cell culture and identified by transmission electron microscopy and Western blot. C57BL/6J mice were performed of full-thickness skin wounds and treated with exosomal suspension or TSG-6-neutralizing antibody. H&E staining was subjected to observe the pathological changes of scar tissues. Immunohistochemistry, ELISA, real time-PCR and Western blot were applied to detect the expressions of relevant molecules. The results showed that subcutaneous injection of TSG-6 overexpressed MSC-derived exosomes effectively ameliorated scar pathological injury, decreased inflammatory molecular secretion and attenuated collagen deposition in a mouse skin wound model. Reversely, knockdown of TSG-6 abrogated the therapeutic effect of MSC-derived exosomes on scarring. Moreover, TSG-6-neutralizing antibody counteracted the effect of TSG-6 overexpressed MSC-derived exosomes in preventing scar formation. In conclusion, we demonstrated that exosomes derived from TSG-6 modified MSCs suppressed scar formation via reducing inflammation and inhibiting collagen deposition.

Leading edge: emerging drug, cell, and gene therapies for junctional epidermolysis bullosa

INTRODUCTION

Junctional epidermolysis bullosa (JEB) is a rare inherited genetic disorder with limited treatments beyond palliative care. A major hallmark of JEB is skin blistering caused by functional loss or complete absence of major structural proteins of the skin. Impaired wound healing in patients with JEB gives rise to chronic cutaneous ulcers that require daily care. Wound care and infection control are the current standard of care for this patient population.

AREAS COVERED

This review covers research and clinical implementation of emerging drug, cell, and gene therapies for JEB. Current clinical trials use topical drug delivery to manipulate the inflammation and re-epithelialization phases of wound healing or promote premature stop codon readthrough to accelerate chronic wound closure. Allogeneic cell therapies for JEB have been largely unsuccessful, with autologous skin grafting emerging as a reliable method of resolving the cutaneous manifestations of JEB. Genetic correction and transplant of autologous keratinocytes have demonstrated persistent amelioration of chronic wounds in a subset of patients.

EXPERT OPINION

Emerging therapies address the cutaneous symptoms of JEB but are unable to attend to systemic manifestations of the disease. Investigations into the molecular mechanism(s) underpinning the failure of systemic allogeneic cell therapies are necessary to expand the range of effective JEB therapies.

Prolactin may serve as a regulator to promote vocal fold wound healing

Reduced prolactin (PRL) has been shown to delay wound healing with a limited understanding of the underlying mechanisms. Here, we aim to explore the role of PRL in the repair of vocal fold (VF) injury. A microarray was used to detect the expressed levels of PRL in rat VF tissue at 1, 4, and 8 weeks after VF injury compared with normal uninjured rats. Then, a systematic bioinformatics analysis has been conducted to explore the literature-based biology network and signaling pathways involved in the repair of VF injury. The expression of PRL was significantly decreased in all VF injury groups (week 1, 4, and 8) compared with the control group (F stats = 280.34; P=4.88e-14), with no significant difference among the three VF injury groups (F stats = 1.97; P=0.18). Wounding has been shown to interfere with both PRL-promoting and inhibiting pathways that were involved in wound healing, including 11 PRL inhibitors and 6 PRL promoters. Our results reveal decreased PRL expression levels in VF injury, which is not in favor of the wound healing. The pathways identified may help in understanding the role of PRL as a treatment target for VF wound healing.

Disabled Homolog 2 Controls Prometastatic Activity of Tumor-Associated Macrophages

Tumor-associated macrophages (TAM) are regulators of extracellular matrix (ECM) remodeling and metastatic progression, the main cause of cancer-associated death. We found that disabled homolog 2 mitogen-responsive phosphoprotein (DAB2) is highly expressed in tumor-infiltrating TAMs and that its genetic ablation significantly impairs lung metastasis formation. DAB2-expressing TAMs, mainly localized along the tumor-invasive front, participate in integrin recycling, ECM remodeling, and directional migration in a tridimensional matrix. DAB2⁺ macrophages escort the invasive dissemination of cancer cells by a mechanosensing pathway requiring the transcription factor YAP. In human lobular breast and gastric carcinomas, DAB2⁺ TAMs correlated with a poor clinical outcome, identifying DAB2 as potential prognostic biomarker for stratification of patients with cancer. DAB2 is therefore central for the prometastatic activity of TAMs. SIGNIFICANCE: DAB2 expression in macrophages is essential for metastasis formation but not primary tumor growth. Mechanosensing cues, activating the complex YAP-TAZ, regulate DAB2 in macrophages, which in turn controls integrin recycling and ECM remodeling in 3-D tissue matrix. The presence of DAB2⁺ TAMs in patients with cancer correlates with worse prognosis.This article is highlighted in the In This Issue feature, p. 1611.

Molecular Mapping of Hydrogen Sulfide Targets in Normal Human Keratinocytes

Although sulfur-rich thermal waters have ancestrally been used in the context of dermatological conditions, a global mapping of the molecular effects exerted by H2S on human keratinocytes is still lacking. To fill this knowledge gap, we subjected cultured human keratinocytes to distinct amounts of the non-gaseous hydrogen sulfur donor NaHS. We first checked that H2S accumulated in the cytoplasm of keratinocytes under our experimental conditions andused a combination of proteomics, genomics and biochemical approaches to unravel functionally relevant H2S targets in human keratinocytes. We found that the identified targets fall into two main categories: (i) the oxidative stress response molecules superoxide dismutase 2 (SOD2), NAD(P)H quinone dehydrogenase 1 (NQO1) and culin 3 (CUL3) and (ii) the chemokines interleukin-8 (IL-8) and CXCL2. Interestingly, NaHS also stimulated the caspase-1 inflammasome pathway, leading to increased secretion of the pro-inflammatory molecule interleukin-18 (IL-18). Interestingly, the secretion of interleukin-1 beta (IL-1β) was only modestly impacted by NaHS exposure despite a significant accumulation of IL-1β pro-form. Finally, we observed that NaHS significantly hampered the growth of human keratinocyte progenitors and stem cells cultured under clonogenic conditions or as epidermal cell sheets. We conclude that H2S exerts specific molecular effects on normal human keratinocytes.

Acceleration of Skin Wound-Healing Reactions by Autologous Micrograft Tissue Suspension

Background and objectives: Skin grafting is a method usually used in reconstructive surgery to accelerate skin regeneration. This method results frequently in unexpected scar formations. We previously showed that cutaneous wound-healing in normal mice is accelerated by a micrograft (MG) technique. Presently, clinical trials have been performed utilizing this technology; however, the driving mechanisms behind the beneficial effects of this approach remain unclear. In the present study, we focused on five major tissue reactions in wound-healing, namely, regeneration, migration, granulation, neovascularization and contraction. Methods: Morphometrical analysis was performed using tissue samples from the dorsal wounds of mice. Granulation tissue formation, neovascularization and epithelial healing were examined. Results: The wound area correlated well with granulation sizes and neovascularization densities in the granulation tissue. Vascular distribution analysis in the granulation tissue indicated that neovessels extended and reached the subepidermal area in the MG group but was only halfway developed in the control group. Moreover, epithelialization with regeneration and migration was augmented by MG. Myofibroblast is a known machinery for wound contraction that uses α-smooth muscle actin filaments. Their distribution in the granulation tissue was primarily found beneath the regenerated epithelium and was significantly progressed in the MG group. Conclusions: These findings indicated that MG accelerated a series of wound-healing reactions and could be useful for treating intractable wounds in clinical situations.

Position of macula lutea and presence of proliferative vitreoretinopathy affect vitreous cytokine expression in rhegmatogenous retinal detachment

Our purpose was to evaluate the concentrations of vitreous cytokines in patients with rhegmatogenous retinal detachment (RRD). We hypothesized that patients with macula on RRD have lower levels of cytokines compared to patients with macula off RRD and proliferative vitreoretinopathy (PVR). Vitreous fluids were collected during 23G pars plana vitrectomy from 58 eyes of 58 patients. Indication for vitrectomy included macula off and macula on RRD, PVR, and idiopathic epiretinal membrane (ERM). A multiplex chemiluminescent immunoassay was performed to measure the concentrations of 48 cytokines, chemokines, and growth factors. Levels of HGF, IL-6, IL-8, IL-16, IFN-gamma, MCP-1, and MIF were significantly higher in all groups of retinal detachment compared to ERM. Levels of CTACK, eotaxin, G-CSF, IP-10, MIG, SCF, SCGF-beta, SDF-1alpha were significantly higher in PVR compared to macula on RRD and ERM. Levels of IL-1ra, IL-5, IL-9, M-CSF, MIP-1alpha, and TRIAL were significantly higher in PVR compared to macula on RRD. Our results indicate that the position of macula lutea and the presence of PVR significantly influence vitreous cytokine expression. The detected proteins may serve as biomarkers to estimate the possibility of PVR formation and may help to invent personalized therapeutic strategies to slow down or prevent PVR.

Influence of Systemic Inflammatory Response to Appearance of New Foci of Chronic Inflammation

Changes in the body in the presence of a chronic inflammatory process, even of a low intensity, lead to the change in the body’s reactivity, having a negative impact on the development, course and clinical prognosis of newly emerging inflammatory processes. Structural changes in the vascular network in the focus of chronic inflammation and following cellular reactions that occur under the action of chemokines and cytokines are the basis for the maintenance and development of the phlogogenic process, including subsequent structural changes in tissues. The failure to resolve the inflammation leads not only to the persistence of the process in the primary focus, but also to the formation of a multitude of the so-calledpathological circles, included at the system level, causing the imbalance among proinflammatory, anti-inflammatory and pro-resolving factors. As a result, conditions are formed for the emergence of new foci of the inflammation in other organs and tissues and in the case of their realization, new vicious circles are formed that contribute to the maintenance and progression of the inflammation. The complex application of etio-tropic, pathogenetic and sanogenetic principles of the treatment allows intensifying of the formation of specialized pro-resolving factors with the elimination of their relative insufficiency, contributing to the reduction of newly formed vessels and to the restoration of the normal cellular composition of the tissue as well as to the resolution of inflammation.

Development and characterization of a superabsorbing hydrogel film containing Ulmus davidiana var. Japonica root bark and pullulan for skin wound healing

Ulmus davidiana var. japonica (UD) has widely been used in Korean traditional medicine for the treatment of various types of diseases including inflammation and skin wounds. The UD root bark powders possess gelling activity with an excellent capacity for absorbing water. This distinct property could make the UD root bark powders to be a great material for manufacturing a gel film specifically for the healing of large and highly exudating wounds (e.g., pressure sores and diabetic ulcers). In this research, we separated the UD root bark powder into 4 different samples based on their sizes and then tested their water absorption capacity and flowability. Based on these results, 75-150 μm sized and below 75 μm sized samples of UD root bark powders were chosen, and UD gel films were prepared. The UD gel films showed good thermal stability and mechanically improved properties compared with pullulan only gel film with excellent swelling capacity and favorable skin adhesiveness. Further, in the animal studies with the skin wound mice model, the UD gel films exhibited significant therapeutic effects on accelerating wound closure and dermal regeneration. Overall, this study demonstrated the applicability of UD root bark powders for hydrogel wound dressing materials, and the potential of UD gel films to be superior wound dressings to currently available ones.

Insights into the Role of Innate Immunity in Cervicovaginal Papillomavirus Infection from Studies Using Gene-Deficient Mice

We demonstrate that female C57BL/6J mice are susceptible to a transient lower genital tract infection with MmuPV1 mouse papillomavirus and display focal histopathological abnormalities resembling those of human papillomavirus (HPV) infection. We took advantage of strains of genetically deficient mice to study in vivo the role of innate immune signaling in the control of papillomavirus. At 4 months, we sacrificed MmuPV1-infected mice and measured viral 757/3139 spliced transcripts by TaqMan reverse transcription-PCR (RT-PCR), localization of infection by RNAscope in situ hybridization, and histopathological abnormities by hematoxylin and eosin (H&E) staining. Among mice deficient in receptors for pathogen-associated molecular patterns, MyD88^-/- and STING^-/- mice had 1,350 and 80 copies of spliced transcripts/μg RNA, respectively, while no viral expression was detected in MAVS^-/- and Ripk2^-/- mice. Mice deficient in an adaptor molecule, STAT1^-/-, for interferon signaling had 46,000 copies/μg RNA. Among mice with targeted deficiencies in the inflammatory response, interleukin-1 receptor knockout (IL-1R^-/-) and caspase-1^-/- mice had 350 and 30 copies/μg RNA, respectively. Among mice deficient in chemokine receptors, CCR6^-/- mice had 120 copies/μg RNA, while CXCR2^-/- and CXCR3^-/- mice were negative. RNAscope confirmed focal infection in MyD88^-/-, STAT1^-/-, and CCR6^-/- mice but was negative for other gene-deficient mice. Histological abnormalities were seen only in the latter mice. Our findings and the literature support a working model of innate immunity to papillomaviruses involving the activation of a MyD88-dependent pathway and IL-1 receptor signaling, control of viral replication by interferon-stimulated genes, and clearance of virus-transformed dysplastic cells by the action of the CCR6/CCL20 axis.IMPORTANCE Papillomaviruses infect stratified squamous epithelia, and the viral life cycle is linked to epithelial differentiation. Additionally, changes occur in viral and host gene expression, and immune cells are activated to modulate the infectious process. In vitro studies with keratinocytes cannot fully model the complex viral and host responses and do not reflect the contribution of local and migrating immune cells. We show that female C57BL/6J mice are susceptible to a transient papillomavirus cervicovaginal infection, and mice deficient in select genes involved in innate immune responses are susceptible to persistent infection with variable manifestations of histopathological abnormalities. The results of our studies support a working model of innate immunity to papillomaviruses, and the model provides a framework for more in-depth studies. A better understanding of mechanisms of early viral clearance and the development of approaches to induce clearance will be important for cancer prevention and the treatment of HPV-related diseases.

Effect of VX‑765 on the transcriptome profile of mice spinal cords with acute injury

Previous studies have shown that caspase-1 plays an important role in the acute inflammatory response of spinal cord injury (SCI). VX‑765, a novel and irreversible caspase‑1 inhibitor, has been reported to effectively intervene in inflammation. However, the effect of VX‑765 on genome‑wide transcription in acutely injured spinal cords remains unknown. Therefore, in the present study, RNA‑sequencing (RNA‑Seq) was used to analyze the effect of VX‑765 on the local expression of gene transcription 8 h following injury. The differentially expressed genes (DEGs) underwent enrichment analysis of functions and pathways by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses, respectively. Parallel analysis of western blot confirmed that VX‑765 can effectively inhibit the expression and activation of caspase‑1. RNA‑Seq showed that VX‑765 treatment resulted in 1,137 upregulated and 1,762 downregulated DEGs. These downregulated DEGs and their associated signaling pathways, such as focal adhesion, cytokine‑cytokine receptor interaction, leukocyte transendothelial migration, extracellular matrix‑receptor interaction, phosphatidylinositol 3‑kinase‑protein kinase B, Rap1 and hypoxia inducible factor‑1 signaling pathway, are mainly associated with inflammatory response, local hypoxia, macrophage differentiation, adhesion migration and apoptosis of local cells. This suggests that the application of VX‑765 in the acute phase can improve the local microenvironment of SCI by inhibiting caspase‑1. However, whether VX‑765 can be used as a therapeutic drug for SCI requires further exploration. The sequence data have been deposited into the Sequence Read Archive (https://www.ncbi.nlm.nih.gov/sra/PRJNA548970).

Lipoconstruct surface topography grating size influences vascularization onset in the dorsal skinfold chamber model

After skin tissue injury or pathological removal, vascularization timing is paramount in graft survival. As full thickness skin grafts often fail to become perfused over larger surfaces, split-thickness grafts are preferred and can be used together with biomaterials, which themselves are non-angiogenic. One way of promoting vascular ingrowth is to "pre-vascularize" an engineered substitute by introducing endothelial cells (ECs). Since it has been previously demonstrated that surface structured biomaterials have an effect on wound healing, skin regeneration, and fibrosis reduction, we proposed that a microvascular-rich lipoconstruct with anisotropic topographical cues could be a clinically translatable vascularization approach. Murine lipofragments were formed with three polydimethylsiloxane molds (flat, 5 µm, and 50 µm parallel gratings) and implanted into the dorsal skinfold chamber of male C57BL/6 mice. Vascular ingrowth was observed through intravital microscopy over 21 days and further assessed by histology and protein identification. Our investigation revealed that topographical feature size influenced the commencement of neovascular ingrowth, with 5 µm gratings exhibiting early construct perfusion at 3 days post-operation, and 50 µm being delayed until day 5. We therefore postulate that surface structured lipoconstructs may serve as an easily obtained and produced construct suitable for providing soft tissue and ECs to tissue defects. STATEMENT OF SIGNIFICANCE: Skin graft failures due to inadequate or uneven perfusion frequently occur and can be even more complicated in deep, difficult to heal wounds, or bone coverage. In complex injuries, biomaterials are often used to cover bone structures with a standard split thickness graft; however, perfusion can take up to 3 weeks. Thus, any means to promote faster and uniform vascularization could significantly reduce healing time, as well as lower patient down-time. As pre-vascularized constructs have reported success in research, we created a cost-efficient, translatable method with no additional laboratory time as adipose tissue can be harvested and used immediately. We further used surface topography as an aspect to modulate construct perfusion, which has been reported for the first time here.

CCL28-induced CCR10/eNOS interaction in angiogenesis and skin wound healing

Chemokines and their receptors play important roles in vascular homeostasis, development, and angiogenesis. Little is known regarding the molecular signaling mechanisms activated by CCL28 chemokine via its primary receptor CCR10 in endothelial cells (ECs). Here, we test the hypothesis that CCL28/CCR10 signaling plays an important role in regulating skin wound angiogenesis through endothelial nitric oxide synthase (eNOS)-dependent Src, PI3K, and MAPK signaling. We observed nitric oxide (NO) production in human primary ECs stimulated with exogenous CCL28, which also induced direct binding of CCR10 and eNOS resulting in inhibition of eNOS activity. Knockdown of CCR10 with siRNA lead to reduced eNOS expression and tube formation suggesting the involvement of CCR10 in EC angiogenesis. Based on this interaction, we engineered a myristoylated 7 amino acid CCR10-binding domain (Myr-CBD7) peptide and showed that this can block eNOS interaction with CCR10, but not with calmodulin, resulting in upregulation of eNOS activity. Importantly, topical administration of Myr-CBD7 peptide on mouse dermal wounds not only blocked CCR10-eNOS interaction, but also enhanced expression of eNOS, CD31, and IL-4 with reduction of CCL28 and IL-6 levels associated with improved wound healing. These results point to a potential therapeutic strategy to upregulate NO bioavailability, enhance angiogenesis, and improve wound healing by disrupting CCL28-activated CCR10-eNOS interaction.

Therapeutic Effects of Hyperbaric Oxygen in the Process of Wound Healing

Chronic and non-healing wounds, especially diabetic foot ulcers and radiation injuries, imply remarkable morbidity with a significant effect on the quality of life and a high sanitary cost. The management of these wounds requires complex actions such as surgical debris, antibiotic treatment, dressings and even revascularization. These wounds are characterized by poor oxygen supply resulting in inadequate oxygenation of the affected tissue. The adjuvant treatment with hyperbaric oxygen therapy (HBOT) may increase tissue oxygenation favoring the healing of wounds which do not respond to the usual clinical care. The increase in the partial pressure of oxygen contributes to cover the energy demands necessary for the healing process and reduces the incidence of infections. Moreover, the increase in oxygen leads to the production of reactive species with hormetic activity, acting on signaling pathways that modulate the synthesis of inflammation mediators, antioxidants and growth factors which can contribute to the healing process. Studies performed with cell cultures and in animal models seem to demonstrate the beneficial effects of HBOT. However, clinical trials do not show such conclusive results; thus, additional randomized placebo-controlled studies are necessary to determine the real efficacy of HBOT and the mechanism of action for various types of wounds.

Medium conditioned by human mesenchymal stromal cells reverses low serum and hypoxia-induced inhibition of wound closure

Chronic wounds, such as pressure ulcers, are a common complication of impaired peripheral circulation, such as in advanced diabetes. Factors secreted by mesenchymal stromal cells (MSCs) have been shown to enhance wound healing in vitro and in vivo. However, there is little understanding of the impact of the chronic wound environment, namely the limited supply of nutrients and oxygen, on the ability of wound cells to respond to MSCs. In this study, we first established the effects of hypoxia (1% O2) and low serum (1% serum) concentration on the proliferation and migration of keratinocytes. We found that hypoxia and low serum significantly slowed down these processes. Next, we found that supplementation with human MSC-concentrated conditioned media (hMSC-CM) enhanced both cell migration and proliferation in the presence of hypoxia and low serum. Furthermore, low serum and hypoxia decreased cell spreading and F-actin expression, which was reversed in the presence of hMSC-CM. Several wound healing mediators were identified in hMSC-CM, including IL-5, IL-6, IL-8, IL-9, IP-10, MCP-1, FGF-2, and VEGF. This study suggests that the concentrated secretome of human MSCs can reverse the inhibitory effect of hypoxia and low serum on keratinocyte proliferation and migration. This phenomenon may contribute to the beneficial effects of hMSC-CM on wound healing in vivo.