IL-22R Ligands IL-20, IL-22, and IL-24 Promote Wound Healing in Diabetic db/db Mice

ROCK1 inhibition improves wound healing in diabetes via RIPK4/AMPK pathway

Refractory wounds are a severe complication of diabetes mellitus that often leads to amputation because of the lack of effective treatments and therapeutic targets. The pathogenesis of refractory wounds is complex, involving many types of cells. Rho-associated protein kinase-1 (ROCK1) phosphorylates a series of substrates that trigger downstream signaling pathways, affecting multiple cellular processes, including cell migration, communication, and proliferation. The present study investigated the role of ROCK1 in diabetic wound healing and molecular mechanisms. Our results showed that ROCK1 expression significantly increased in wound granulation tissues in diabetic patients, streptozotocin (STZ)-induced diabetic mice, and db/db diabetic mice. Wound healing and blood perfusion were dose-dependently improved by the ROCK1 inhibitor fasudil in diabetic mice. In endothelial cells, fasudil and ROCK1 siRNA significantly elevated the phosphorylation of adenosine monophosphate-activated protein kinase at Thr172 (pThr172-AMPKα), the activity of endothelial nitric oxide synthase (eNOS), and suppressed the levels of mitochondrial reactive oxygen species (mtROS) and nitrotyrosine formation. Experiments using integrated bioinformatics analysis and coimmunoprecipitation established that ROCK1 inhibited pThr172-AMPKα by binding to receptor-interacting serine/threonine kinase 4 (RIPK4). These results suggest that fasudil accelerated wound repair and improved angiogenesis at least partially through the ROCK1/RIPK4/AMPK pathway. Fasudil may be a potential treatment for refractory wounds in diabetic patients.

The role of FGF-21 in promoting diabetic wound healing by modulating high glucose-induced inflammation

Background

Wound healing is a complex biological process that can be impaired in individuals with diabetes. Diabetic wounds are a serious complication of diabetes that require promoting diagnosis and effective treatment. FGF-21, a member of the endocrine FGF factors family, has caught the spotlight in the treatment of diabetes for its beneficial effects on accelerating human glucose uptake and fat catabolism. However, the therapeutic efficacy of FGF-21 in promoting diabetic wounds remains unknown. This study aims to evaluate the therapeutic potential of FGF-21 in promoting diabetic wound healing.

Methods

we investigated the effects of FGF-21 on wound healing related-cells under high-glucose conditions using various assays such as CCK8, scratch assay, flow cytometry analysis, endothelial tube-formation assay, and transmission electron microscopy. Furthermore, we used db/db mice to verify the healing-promoting therapeutic effects of FGF-21 on diabetic wounds. We also conducted qRT-PCR, Western blot, and immunofluorescence staining analyses to elucidate the underlying mechanism.

Result

Our results indicate that FGF-21 treatment restored hyperglycemic damage on endothelial cell proliferation, migration, and tube-forming ability. It also reduced endothelial cell death rates under high-glucose conditions. TEM analysis showed that FGF-21 treatment effectively restored mitochondrial damage and morphological changes in endothelial cells caused by glucose. Additionally, qRT-PCR and Western blot analysis indicated that FGF-21 treatment restored inflammatory responses caused by hyperglycemic damage. Animal experiments confirmed these findings, suggesting that FGF-21 may be a promising candidate for the treatment of non-healing diabetic wounds due to its effectiveness in stimulating angiogenesis and anti-inflammatory function.

Conclusion

Our study provides evidence that FGF-21 is an essential regulator of wound-related cells under high-glucose conditions and has the potential to be a novel therapeutic target for accelerating diabetic wound healing.

γδ T Cells Mediate a Requisite Portion of a Wound Healing Response Triggered by Cutaneous Poxvirus Infection

Infection at barrier sites, e.g., skin, activates local immune defenses that limit pathogen spread, while preserving tissue integrity. Phenotypically distinct γδ T cell populations reside in skin, where they shape immunity to cutaneous infection prior to onset of an adaptive immune response by conventional αβ CD4+ (TCD4+) and CD8+ (TCD8+) T cells. To examine the mechanisms used by γδ T cells to control cutaneous virus replication and tissue pathology, we examined γδ T cells after infection with vaccinia virus (VACV). Resident γδ T cells expanded and combined with recruited γδ T cells to control pathology after VACV infection. However, γδ T cells did not play a role in control of local virus replication or blockade of systemic virus spread. We identified a unique wound healing signature that has features common to, but also features that antagonize, the sterile cutaneous wound healing response. Tissue repair generally occurs after clearance of a pathogen, but viral wound healing started prior to the peak of virus replication in the skin. γδ T cells contributed to wound healing through induction of multiple cytokines/growth factors required for efficient wound closure. Therefore, γδ T cells modulate the wound healing response following cutaneous virus infection, maintaining skin barrier function to prevent secondary bacterial infection.

CsIL-20, a tongue sole interleukin-20, negatively mediates leucocyte activity and antibacterial defense

Interleukin-20 (IL-20), as an essential member of IL-10 family, plays vital roles in mammalian immunological response such as antimicrobial, inflammation, hematopoiesis, and immune diseases. In teleost, the study about immune antimicrobial function of IL-20 is largely scarce. In this article, we revealed the expression profiles and the immunological functions of the IL-20 (CsIL-20) in tongue sole Cynoglossus semilaevis. CsIL-20 is composed of 183 amino acid residues, with seven cysteine residues and a typical IL-10 domain which comprises six α-helices and two β-sheets, and shares 34.4-71.2 % identities with other teleost IL-20. CsIL-20 was constitutively expressed in a variety of tissues and regulated by bacterial invasion, and the recombinant CsIL-20 (rCsIL-20) could bind to different bacteria. In vitro rCsIL-20 could interact with the membrane of peripheral blood leukocytes (PBLs), leading to the attenuation of reactive oxygen species (ROS) production and acid phosphatase activity in PBLs. In line with In vitro results, In vivo rCsIL-20 could obviously suppressed the host immune against bacterial infection. Furthermore, knockdown of CsIL-20 in vivo could markedly enhance the host antibacterial immunity. Collectively, these observations offer new insights into the negative effect of CsIL-20 on antibacterial immunity.

Spinal interleukin-24 contributes to neuropathic pain after peripheral nerve injury through interleukin-20 receptor2 in mice

Neuroinflammation is critically involved in nerve injury-induced neuropathic pain, characterized by local and systemic increased levels of proinflammatory cytokines. Interleukin-24 (IL-24), a key member of the IL-10 family, has been extensively studied for its therapeutic potential in various diseases, including cancer, autoimmune disorders, and bacterial infections, but whether it is involved in the regulation of neuropathic pain caused by peripheral nerve injury (PNI) has not been well established. In this study, we reported that spared nerve injury (SNI) induced a significant upregulation of IL-24 in fibroblasts, neurons, and oligodendrocyte precursor cells (OPCs, also called NG2-glia) in the affected spinal dorsal horns (SDHs), as well as dorsal root ganglions (DRGs). We also found that tumor necrosis factor α (TNF-α) induced the transcriptional expression of IL-24 in cultured fibroblasts, neurons, and NG2-glia; in addition, astrocytes, microglia, and NG2-glia treated with TNF-α exhibited a prominent increase in interleukin-20 receptor 2 (IL-20R2) expression. Furthermore, we evaluated the ability of IL-24 and IL-20R2 to attenuate pain in preclinical models of neuropathic pain. Intrathecal (i.t.) injection of IL-24 neutralizing antibody or IL-20R2 neutralizing antibody could effectively alleviate mechanical allodynia and thermal hyperalgesia after PNI. Similarly, intrathecal injection of IL-24 siRNA or IL-20R2 siRNA also alleviated mechanical allodynia after SNI. The inhibition of IL-24 reduced SNI-induced proinflammatory cytokine (IL-1β and TNF-α) production and increased anti-inflammatory cytokine (IL-10) production. Meanwhile, the inhibition of IL-20R2 also decreased IL-1β mRNA expression after SNI. Collectively, our findings revealed that IL-24/IL-20R might contribute to neuropathic pain through inflammatory response. Therefore, targeting IL-24 could be a promising strategy for treating neuropathic pain induced by PNI.

Investigating Inflammatory Markers in Wound Healing: Understanding Implications and Identifying Artifacts

Understanding the complex interplay of pro-inflammatory and anti-inflammatory cytokines is crucial in the field of wound healing, as it holds the key to developing effective therapeutics. In the initial stages of wound healing, pro-inflammatory cytokines like IL-1β, IL-6, TNF-α, and various chemokines play vital roles in recruiting cells for debris clearance and the recruitment of growth factors. Careful regulation and timely resolution of this early inflammation are essential for optimal wound repair. As the healing process progresses, anti-inflammatory proteins such as IL-10 and IL-4 become instrumental in facilitating the transition to later stages where pro-inflammatory cytokines promote angiogenesis and wound remodeling. This Perspective underscores the complexity of inflammatory cytokines in wound healing research and emphasizes the need for comprehensive and unbiased methodologies in their evaluation. For robust and reliable results in wound-healing research, a more holistic approach is necessary-one that considers the roles, interactions, and timing of biological molecules, alongside careful sampling and evaluation strategies.

Cytokines and Regulating Epithelial Cell Division

Physiologically, cytokines play an extremely important role in maintaining cellular and subcellular homeostasis, as they interact almost with every cell in the organism. Therefore, cytokines play a significantly critical role in the field of pathogenic pharmacological therapy of different types of pathologies. Cytokine is a large family containing many subfamilies and can be evaluated into groups according to their action on epithelial cell proliferation; stimulatory include transforming growth factor-α (TGF-α), Interlukine-22 (IL-22), IL-13, IL-6, IL-1RA and IL-17 and inhibitory include IL-1α, interferon type I (IFN type I), and TGF-β. The balance between stimulatory and inhibitory cytokines is essential for maintaining normal epithelial cell turnover and tissue homeostasis. Dysregulation of cytokine production can contribute to various pathological conditions, including inflammatory disorders, tissue damage, and cancer. Several cytokines have shown the ability to affect programmed cell death (apoptosis) and the capability to suppress non-purpose cell proliferation. Clinically, understanding the role of cytokines' role in epithelial tissue is crucial for evaluating a novel therapeutic target that can be of use as a new tactic in the management of carcinomas and tissue healing capacity. The review provides a comprehensive and up-to-date synthesis of current knowledge regarding the multifaceted effects of cytokines on epithelial cell proliferation, with a particular emphasis on the intestinal epithelium. Also, the paper will highlight the diverse signaling pathways activated by cytokines and their downstream consequences on epithelial cell division. It will also explore the potential therapeutic implications of targeting cytokine- epithelial cell interactions in the context of various diseases.

Interleukin-22 promotes proliferation and reverses LPS-induced apoptosis and steroidogenesis attenuation in human ovarian granulosa cells: implications for polycystic ovary syndrome pathogenesis

OBJECTIVE

Interleukin 22 (IL-22) plays a role in inflammatory diseases. However, whether IL-22 affects the function of ovarian granulosa cells (GCs) and its relationship with Polycystic Ovary Syndrome (PCOS)remains unclear.

METHODS

We investigated the level of IL-22 in human follicular fluid using ELISA. The expression and localization of the IL-22 receptor 1 (IL-22R1) in GCs were investigated by RT-PCR and immunofluorescence staining, respectively. The proliferation of KGN cells (human GCs line) was assessed by CCK-8 assay and EdU assay after treatment with recombinant human IL-22 (rhIL-22) and lipopolysaccharide (LPS). Apoptosis was assessed using flow cytometry. Apoptotic proteins and steroidogenic genes were detected by western blotting.

RESULTS

ELISA's results showed that compared with the control group, PCOS patients showed lower expression of IL-22 in follicular fluid. Immunofluorescence showed that IL-22R1 is expressed and localized in human granulosa cell membranes. IL-22 promoted cell proliferation and reversed LPS-induced inhibition of cell proliferation. IL-22 alone did not affect apoptotic or steroidogenic protein expression, however, it reversed LPS-induced apoptosis via downregulation of Bcl-2, upregulation of Bax and cleaved caspase-3, and restoration of LPS-downregulated StAR, CYP11A1, and CYP19A1 expression. Western blotting confirmed that IL-22 activated the JAK2/STAT3 signaling.

CONCLUSION

IL-22 promotes cell proliferation, inhibits apoptosis, and regulates KGN cell steroidogenesis confronted with LPS, and decreased IL-22 may be involved in the development of PCOS.

IL-20 Cytokines Are Involved in the Repair of Airway Epithelial Barrier: Implication in Exposure to Cigarette Smoke and in COPD Pathology

BACKGROUND

Dysregulated inflammation as seen in chronic obstructive pulmonary disease (COPD) is associated with impaired wound healing. IL-20 cytokines are known to be involved in wound healing processes. The purpose of this study was to use ex vivo and in vitro approaches mimicking COPD to evaluate the potential modulatory role of interleukin-20 (IL-20) on the inflammatory and healing responses to epithelial wounding.

METHODS

The expression of IL-20 cytokines and their receptors was investigated in lung-derived samples collected from non-COPD and COPD patients, from mice chronically exposed to cigarette smoke and from airway epithelial cells from humans and mice exposed in vitro to cigarette smoke. To investigate the role of IL-20 cytokines in wound healing, experiments were performed using a blocking anti-IL-20Rb antibody.

RESULTS

Of interest, IL-20 cytokines and their receptors were expressed in bronchial mucosa, especially on airway epithelial cells. Their expression correlated with the disease severity. Blocking these cytokines in a COPD context improved the repair processes after a lesion induced by scratching the epithelial layer.

CONCLUSIONS

Collectively, this study highlights the implication of IL-20 cytokines in the repair of the airway epithelium and in the pathology of COPD. IL-20 subfamily cytokines might provide therapeutic benefit for patients with COPD to improve epithelial healing.

Menstrual blood-derived mesenchymal stromal cells: impact of preconditioning on the cargo of extracellular vesicles as potential therapeutics

BACKGROUND

Mesenchymal stromal cells (MSCs) have been shown to exert their therapeutic effects through the secretion of broad spectrum of paracrine factors, including extracellular vesicles (EVs). Accordingly, EVs are being pursued as a promising alternative to cell-based therapies. Menstrual blood-derived stromal cells (MenSCs) are a type of MSC that, due to their immunomodulatory and regenerative properties, have emerged as an innovative source. Additionally, new strategies of cell priming may potentially alter the concentration and cargo of released EVs, leading to modification of their biological properties. In this study, we aimed to characterize the EVs released by MenSCs and compare their therapeutic potential under three different preconditioning conditions (proinflammatory stimuli, physioxia, and acute hypoxia).

METHODS

MenSCs were isolated from five healthy women. Following culturing to 80% confluence, MenSCs were exposed to different priming conditions: basal (21% O₂), proinflammatory stimuli (IFNγ and TNFα, 21% O₂), physioxia (1-2% O₂), and acute hypoxia (< 1% O₂) for 48-72 h. Conditioned media from MenSCs was collected after 48 h and EVs were isolated by a combination of ultra-filtration and differential centrifugation. An extensive characterization ranging from nano-flow cytometry (nFC) to quantitative high-throughput shotgun proteomics was performed. Bioinformatics analyses were used to derive hypotheses on their biological properties.

RESULTS

No differences in the morphology, size, or number of EVs released were detected between priming conditions. The proteome analysis associated with basal MenSC-EVs prominently revealed their immunomodulatory and regenerative capabilities. Furthermore, quantitative proteomic analysis of differentially produced MenSC-EVs provided sufficient evidence for the utility of the differential preconditioning in purpose-tailoring EVs for their therapeutic application: proinflammatory priming enhanced the anti-inflammatory, regenerative and immunomodulatory capacity in the innate response of EVs, physioxia priming also improves tissue regeneration, angiogenesis and their immunomodulatory capacity targeting on the adaptive response, while acute hypoxia priming, increased hemostasis and apoptotic processes regulation in MenSC-EVs, also by stimulating immunomodulation mainly through the adaptive response.

CONCLUSIONS

Priming of MenSCs under proinflammatory and hypoxic conditions affected the cargo proteome of EVs released, resulting in different therapeutic potential, and thus warrants experimental exploration with the aim to generate better-defined MSC-derived bioproducts.

A tissue injury sensing and repair pathway distinct from host pathogen defense

Pathogen infection and tissue injury are universal insults that disrupt homeostasis. Innate immunity senses microbial infections and induces cytokines/chemokines to activate resistance mechanisms. Here, we show that, in contrast to most pathogen-induced cytokines, interleukin-24 (IL-24) is predominately induced by barrier epithelial progenitors after tissue injury and is independent of microbiome or adaptive immunity. Moreover, Il24 ablation in mice impedes not only epidermal proliferation and re-epithelialization but also capillary and fibroblast regeneration within the dermal wound bed. Conversely, ectopic IL-24 induction in the homeostatic epidermis triggers global epithelial-mesenchymal tissue repair responses. Mechanistically, Il24 expression depends upon both epithelial IL24-receptor/STAT3 signaling and hypoxia-stabilized HIF1α, which converge following injury to trigger autocrine and paracrine signaling involving IL-24-mediated receptor signaling and metabolic regulation. Thus, parallel to innate immune sensing of pathogens to resolve infections, epithelial stem cells sense injury signals to orchestrate IL-24-mediated tissue repair.

Robust classification of wound healing stages in both mice and humans for acute and burn wounds based on transcriptomic data

BACKGROUND

Wound healing involves careful coordination among various cell types carrying out unique or even multifaceted functions. The abstraction of this complex dynamic process into four primary wound stages is essential to the study of wound care for timing treatment and tracking wound progression. For example, a treatment that may promote healing in the inflammatory stage may prove detrimental in the proliferative stage. Additionally, the time scale of individual responses varies widely across and within the same species. Therefore, a robust method to assess wound stages can help advance translational work from animals to humans.

RESULTS

In this work, we present a data-driven model that robustly identifies the dominant wound healing stage using transcriptomic data from biopsies gathered from mouse and human wounds, both burn and surgical. A training dataset composed of publicly available transcriptomic arrays is used to derive 58 shared genes that are commonly differentially expressed. They are divided into 5 clusters based on temporal gene expression dynamics. The clusters represent a 5-dimensional parametric space containing the wound healing trajectory. We then create a mathematical classification algorithm in the 5-dimensional space and demonstrate that it can distinguish between the four stages of wound healing: hemostasis, inflammation, proliferation, and remodeling.

CONCLUSIONS

In this work, we present an algorithm for wound stage detection based on gene expression. This work suggests that there are universal characteristics of gene expression in wound healing stages despite the seeming disparities across species and wounds. Our algorithm performs well for human and mouse wounds of both burn and surgical types. The algorithm has the potential to serve as a diagnostic tool that can advance precision wound care by providing a way of tracking wound healing progression with more accuracy and finer temporal resolution compared to visual indicators. This increases the potential for preventive action.

Pentoxifylline/Chitosan Films on Wound Healing: In Vitro/In Vivo Evaluation

This study aimed to develop films of chitosan (CSF) associated with pentoxifylline (PTX) for healing cutaneous wounds. These films were prepared at two concentrations, F1 (2.0 mg/mL) and F2 (4.0 mg/mL), and the interactions between the materials, structural characteristics, in vitro release, and morphometric aspects of skin wounds in vivo were evaluated. The formation of the CSF film with acetic acid modifies the polymeric structure, and the PTX demonstrates interaction with the CSF, in a semi-crystalline structure, for all concentrations. The release for all films was proportional to the concentration, with two phases: a fast one of ≤2 h and a slow one of >2 h, releasing 82.72 and 88.46% of the drug after 72 h, being governed by the Fickian diffusion mechanism. The wounds of the mice demonstrate a reduction of up to 60% in the area on day 2 for F2 when compared to CSF, F1, and positive control, and this characteristic of faster healing speed for F2 continues until the ninth day with wound reduction of 85%, 82%, and 90% for CSF, F1, and F2, respectively. Therefore, the combination of CSF and PTX is effective in their formation and incorporation, demonstrating that a higher concentration of PTX accelerates skin-wound reduction.

IL-20 Activates ERK1/2 and Suppresses Splicing of X-Box Protein-1 in Intestinal Epithelial Cells but Does Not Improve Pathology in Acute or Chronic Models of Colitis

The cytokine Interleukin (IL)-20 belongs to the IL-10 superfamily. IL-20 levels are reported to increase in the intestines of Ulcerative Colitis (UC) patients, however not much is known about its effects on intestinal epithelial cells. Here, we investigated the influence of IL-20 on intestinal epithelial cell lines and primary intestinal organoid cultures. By using chemical-induced (dextran sodium sulphate; DSS) colitis and a spontaneous model of colitis (Winnie mice), we assess whether recombinant IL-20 treatment is beneficial in reducing/improving pathology. Following stimulation with IL-20, intestinal primary organoids from wild-type and Winnie mice increased the expression of ERK1/2. However, this was lost when cells were differentiated into secretory goblet cells. Importantly, IL-20 treatment significantly reduced endoplasmic reticulum (ER) stress, as measured by spliced-XBP1 in epithelial cells, and this effect was lost in the goblet cells. IL-20 treatment in vivo in the DSS and Winnie models had minimal effects on pathology, but a decrease in macrophage activation was noted. Taken together, these data suggest a possible, but subtle role of IL-20 on epithelial cells in vivo. The therapeutic potential of IL-20 could be harnessed by the development of a targeted therapy or combination therapy to improve the healing of the mucosal barrier.

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.

Wound healing in db/db mice with type 2 diabetes using non-contact exposure with an argon non-thermal atmospheric pressure plasma jet device

A non-thermal atmospheric pressure plasma jet (APPJ) may stimulate cells and tissues or result in cell death depending on the intensity of plasma at the target; therefore, we herein investigated the effects of non-thermal plasma under non-contact conditions on the healing of full-thickness wounds in diabetic mice (DM+ group) and normal mice (DM- group). A hydrogen peroxide colorimetric method and high performance liquid chromatography showed that APPJ produced low amounts of reactive oxygen and nitrogen species. Ten-week-old male C57BL/6j mice with normal blood glucose levels (DM- group) and 10-week-old male C57BLKS/J Iar-+Leprdb/+Leprdb mice (DM+ group) received two full-thickness cutaneous wounds (4 mm in diameter) on both sides of the dorsum. Wounds were treated with or without the plasma jet or argon gas for 1 minute and were then covered with a hydrocolloid dressing (Hydrocolloid), according to which mice were divided into the following groups: DM+Plasma, DM+Argon, DM+Hydrocolloid, DM-Plasma, DM-Argon, and DM-Hydrocolloid. Exudate weights, wound areas, and wound area ratios were recorded every day. Hematoxylin and eosin staining was performed to assess re-epithelialization and α-SMA immunohistological staining to evaluate the formation of new blood vessels. Non-thermal plasma under non-contact conditions reduced the production of exudate. Exudate weights were smaller in the DM+Plasma group than in the DM+Hydrocolloid and DM+Argon groups. The wound area ratio was smaller for plasma-treated wounds, and was also smaller in the DM+Plasma group than in the DM+Hydrocolloid and DM+Argon groups on days 1-21 (p<0.01). Wound areas were smaller in the DM-Plasma group than in the DM-Argon group until day 14 and differences were significant on days 1-5 (p<0.01). The percentage of re-epithelialization was significantly higher in the DM+Plasma group than in the DM+Argon and DM+Hydrocolloid groups (p<0.01). The number of new blood vessels that had formed by day 7 was significantly higher in the DM+Plasma group than in the DM+Hydrocolloid and DM+Argon groups (p<0.05). These results indicate that treatment with the current non-thermal plasma APPJ device under non-contact conditions accelerated wound healing in diabetic mice.

IL-17 and IL-22 are pivotal cytokines to delay wound healing of S. aureus and P. aeruginosa infected skin

Introduction

Although the presence of pathogens in skin wounds is known to delay the wound healing process, the mechanisms underlying this delay remain poorly understood. In the present study, we have investigated the regulatory role of proinflammatory cytokines on the healing kinetics of infected wounds.

Methods

We have developed a mouse model of cutaneous wound healing, with or without wound inoculation with Staphylococcus aureus and Pseudomonas aeruginosa, two major pathogens involved in cutaneous wound bacterial infections.

Results

Aseptic excision in C57BL/6 mouse skin induced early expression of IL-1β, TNFα and Oncostatin M (OSM), without detectable expression of IL-22 and IL-17A/F. S. aureus and P. aeruginosa wound inoculation not only increased the expression of IL-1β and OSM, but also induced a strong cutaneous expression of IL-22, IL-17A and IL-17F, along with an increased number of infiltrating IL-17A and/or IL-22-producing γδ T cells. The same cytokine expression pattern was observed in infected human skin wounds. When compared to uninfected wounds, mouse skin infection delayed the wound healing process. Injection of IL-1α, TNFα, OSM, IL-22 and IL-17 together in the wound edges induced delayed wound healing similar to that induced by the bacterial infection. Wound healing experiments in infected Rag2KO mice (deficient in lymphocytes) showed a wound healing kinetic similar to uninfected Rag2KO mice or WT mice. Rag2KO infected-skin lesions expressed lower levels of IL-17 and IL-22 than WT, suggesting that the expression of these cytokines is mainly dependent on γδ T cells in this model. Wound healing was not delayed in infected IL-17R/IL-22KO, comparable to uninfected control mice. Injection of recombinant IL-22 and IL-17 in infected wound edges of Rag2KO mice re-establish the delayed kinetic of wound healing, as in infected WT mice.

Conclusion

These results demonstrate the synergistic and specific effects of IL-22 and IL-17 induced by bacterial infection delay the wound healing process, regardless of the presence of bacteria per se. Therefore, these cytokines play an unexpected role in delayed skin wound healing.

PAQR3 depletion accelerates diabetic wound healing by promoting angiogenesis through inhibiting STUB1-mediated PPARγ degradation

The pathogenesis of diabetic wounds is closely associated with the dysregulation of macrophage polarization. However, the underlying mechanism remains poorly understood. In this study, we aimed to investigate the potential effects of PAQR3 (progestin and adipoQ receptor 3) silencing in accelerating diabetic wound healing. We showed that PAQR3 silencing promoted skin wound healing and angiogenesis in diabetic mice, which was accompanied by enhanced M2 macrophage polarization and elevated expression of PPARγ (peroxisome proliferator-activated receptor γ). PAQR3 silencing also promoted M2 polarization and increased PPARγ protein level in PMA-treated THP-1 cells. Moreover, knockdown of PAQR3 in macrophages enhanced the migration of HaCaT cells and tube formation of HUVECs. The ubiquitination of PPARγ protein in macrophages was repressed by PAQR3 silencing. STUB1 (STIP1 homology and U-box-containing protein 1) binds with the PPARγ protein to mediate PPARγ ubiquitination and degradation in macrophages, which was impaired by PAQR3 silencing. The PPARγ inhibitor, GW9662, or STUB1 overexpression abrogated the enhanced M2 macrophage polarization induced by PAQR3 silencing. Therefore, these findings demonstrates that PAQR3 silencing accelerates diabetic wound healing by promoting M2 macrophage polarization and angiogenesis, which is mediated by the inhibition of STUB1-mediated PPARγ protein ubiquitination and degradation.

The IL-20RB receptor and the IL-20 signaling pathway in regulating host defense in oral mucosal candidiasis

Pseudomembranous candidiasis (thrush), erythematous candidiasis, and fungal esophagitis are infections of the barrier mucosa of the upper gastrointestinal tract. The majority of these infections are caused by Candida albicans, an opportunistic fungal pathogen that frequently exists as a harmless commensal on mucosal surfaces lining the gastrointestinal tract. Oral infections are initiated in the superficial stratified squamous epithelium, in which keratinocytes are the most abundant host cells and are the initial points of contact with C. albicans present in saliva. Intrinsic features of oral keratinocytes are likely to play important roles in host defense and tissue homeostasis in oral candidiasis. One understudied pathway that may be important for modulating oral candidiasis is the IL-20 cytokine signaling pathway that employs keratinocyte IL-20RB receptors as ligands for IL-19, IL-20, and IL-24. We report that production of human oral keratinocyte il24 mRNA and protein are stimulated during co-culture with C. albicans. To test the role of the IL-20 family signaling pathway in oral candidiasis, Il20rb^-/- mice (lacking the IL-20RB receptor) were compared to wild-type mice in a murine model of oropharyngeal candidiasis. Fungal burdens and percent loss in body weight were determined. Despite comparable fungal burdens, the Il20rb^-/- mice exhibited less weight loss over the course of their infection compared to the B6 mice, suggestive of reduced overall disease consequences in the mutant mice. Interference with IL-20 family cytokine signaling may be useful for augmenting the ability of the host to defend itself against pathogens.

Stem Cell-Based Therapeutic Strategies in Diabetic Wound Healing

Impaired wound healing and especially the “all-too-common” occurrence of associated diabetic foot ulcers (DFU) are becoming an increasingly urgent and deteriorating healthcare issue, which drastically impact the quality of life and further heighten the risks of infection and amputation in patients with diabetes mellitus. Amongst the multifactorial wound healing determinants, glycemic dysregulation has been identified to be the primary casual factor of poor wound healing. Unfortunately, current therapeutic modalities merely serve as moderate symptomatic relieves but often fail to completely restore the wound site to its pre-injury state and prevent further recurrence. Stem cell-based therapeutics have been employed for its promising potential to address the root of the problem as they not only exhibit the capacity for self-renewal and differentiation towards multiple lineages, but also have been disclosed to participate in mediating variant growth factors and cytokines. Herein we review the current literatures on the therapeutic benefits of using various kinds of stem cells, including embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs), mesenchymal stem cells (MSCs), and adipose-derived stem cells (ASCs) in diabetic wound healing by searching on the PubMed® Database for publications. This study shall serve as an overview of the current body of research with particular focus on autologous ASCs and the laboratory expandable iPSCs in hope of shedding more light on this attractive therapy so as to elevate the efficacy of wound healing that is almost always compromised in diabetic patients.

Growth Factor and Cytokine Delivery Systems for Wound Healing

Skin wound healing is a highly coordinated process involving multiple tissue-resident and recruited cell types. Cells within the wound microenvironment respond to key secreted factors such as pro-proliferative growth factors and immunomodulatory cytokines to repair the skin and promptly restore its essential barrier role. Therefore, recombinant growth factors and cytokines are promising therapeutics for skin wounds, in particular for large acute wounds such as burns, or wounds associated with underlying pathologies such as nonhealing chronic and diabetic wounds. However, translation of growth factors and cytokines into clinically effective treatments has been limited. Short half-life, poor stability, rapid diffusion, uncontrolled signaling, and systemic side effects are currently the key challenges to developing efficient growth factor- and cytokine-based therapies. To overcome these limitations, novel delivery systems have been developed to improve the regenerative potential of recombinant growth factors and cytokines. In this review, we discuss biomaterial and protein engineering strategies used to optimize the delivery of growth factor and cytokine therapeutics for skin wound treatment.

The Role of T Helper 22 Cells in Dermatological Disorders

T helper 22 (Th22) cells are a newly identified subset of CD4+ T cells that secrete the effector cytokine interleukin 22 (IL-22) upon specific antigen stimulation, barely with IFN-γ or IL-17. Increasing studies have demonstrated that Th22 cells and IL-22 play essential roles in skin barrier defense and skin disease pathogenesis since the IL-22 receptor is widely expressed in the skin, especially in keratinocytes. Herein, we reviewed the characterization, differentiation, and biological activities of Th22 cells and elucidated their roles in skin health and disease. We mainly focused on the intricate crosstalk between Th22 cells and keratinocytes and provided potential therapeutic strategies targeting the Th22/IL-22 signaling pathway.

Quercetin promotes cutaneous wound healing in mice through Wnt/β-catenin signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Oxytropis falcata Bunge is a legume distributed in Northwest China, which is mainly used to treat knife wounds and inflammation. Quercetin is a bioactive flavonoid in O. falcata and becomes a promising healing compound for its angiogenic and anti-inflammatory activities. However, the healing mechanism of quercetin in cutaneous wound remains elusive.

AIM OF THE STUDY

The purpose of this study was to evaluate the healing effect of quercetin on cutaneous wound models in vivo and in vitro, and to reveal the Wnt/β-catenin pathway and Telomerase reverse transcriptase (TERT) involved mechanisms.

MATERIALS AND METHODS

The effects of quercetin on the proliferation and migration of 4 kinds of skin cells were determined by CCK-8 and scratch assay. The wound-healing capacity of quercetin was evaluated in cutaneous wound model of C57BL/6 mice and the wound healing degree was observed by histological staining. The expressions of inflammatory factors, growth factors and the related proteins were detected via Western blot and RT-qPCR analyses. The molecular docking was adopted to evaluate the binding ability of quercetin and TERT.

RESULTS

Quercetin could promote both proliferation and migration of fibroblasts, and enhance cutaneous wound healing capacity in mice. Compared to the control group, the wound healing rates in low (1.5 mg/mL), medium (3.0 mg/mL) and high dose (6.0 mg/mL) quercetin groups reached 94.67%, 97.31% and 98.42%, respectively. Moreover, the dermal structure in quercetin treated mice restored normal and the content of collagen fiber became abundant after administration. The levels of inflammatory factors, including tumor necrosis factor-α, interleukin-1β and interleukin-6 were significantly reduced after quercetin administration. Among which, the level of IL-1β in cutaneous wound was 0.007 times higher than that of the control group when treated with quercetin of high dose (6.0 mg/mL). The improved level of GSH in quercetin treated cutaneous wounds also indicated its higher antioxidant ability. In addition, dose-dependent positive associations were found in the expression levels of vascular endothelial growth factor, fibroblast growth factor and alpha smooth muscle actin in quercetin treated cutaneous wounds. The significantly upregulated protein levels of Wnt and β-catenin further indicated the important role of quercetin in promoting wound healing in mice. According to molecular docking analysis, the formed hydrogen bonds between quercetin and Ala195, Gln308, Asn369 and Lys372 residues of TERT also indicated the indispensable role of TERT in improving wound healing capacity.

CONCLUSION

Quercetin effectively promoted cutaneous wound healing by enhancing the proliferation and migration of fibroblasts, as well as inhibiting inflammation and increasing the expression of growth factors in mice via Wnt/β-catenin signaling pathway and TERT. It provides a basis for a more thorough understanding of mechanism of action of O. falcata Bunge in the treatment of knife wounds and burns.

The Role of IL-22 in Wound Healing. Potential Implications in Clinical Practice

Wound healing is a complex process that is mediated and influenced by several cytokines, chemokines, and growth factors. Interleukin-22 (IL-22) is a cytokine that plays a critical role in tissue regeneration. Our study is a systematic review that addressed the implications of IL-22 in the healing of wounds caused by external factors. Thirteen studies were included in our review, most of them being experimental studies. Three clinical studies underlined the potential role of IL-22 in day-to-day clinical practice. IL-22 plays a central role in wound healing, stimulating the proliferation, migration, and differentiation of the cells involved in tissue repair. However, overexpression of IL-22 can cause negative effects, such as keloid scars or peritoneal adhesions. The results of the presented studies are promising, but further research that validates the roles of IL-22 in clinical practice and analyzes its potential implication in surgical healing is welcomed.

Early Immune Response in Foreign Body Reaction Is Implant/Material Specific

The design of novel biomaterials should directly influence the host-immune system and steer it towards high biocompatibility. To date, new implants/materials have been tested for biocompatibility in vitro in cell cultures and in vivo in animal models. The current methods do not reflect reality (cell cultures) or are very time-consuming and deliver results only after weeks (animal model). In this proof-of-concept study, the suitability of a Whole Blood Stimulation Assay (WBSA) in combination with a Protein Profiler Array (PPA), as a readily available and cost-effective screening tool, was investigated. Three different biomaterials based on poly(lactic-co-glycolic acid (PLGA), calcium sulphate/-carbonate (CS) and poly(methyl methacrylate) (PMMA) were exposed to native whole blood from three volunteers and subsequently screened with a PPA. Individual reproducible protein profiles could be detected for all three materials after 24 h of incubation. The most intense reaction resulted from the use of PLGA, followed by CS. If even marginal differences in implants can be reflected in protein profiles, the combination of WBSA and PPA could serve as an early biocompatibility screening tool in the development of novel biomaterials. This may also lead to a reduction in costs and the amount of animal testing required.

Aging-related olfactory loss is associated with olfactory stem cell transcriptional alterations in humans

BACKGROUNDPresbyosmia, or aging-related olfactory loss, occurs in a majority of humans over age 65 years, yet remains poorly understood, with no specific treatment options. The olfactory epithelium (OE) is the peripheral organ for olfaction and is subject to acquired damage, suggesting a likely site of pathology in aging. Adult stem cells reconstitute the neuroepithelium in response to cell loss under normal conditions. In aged OE, patches of respiratory-like metaplasia have been observed histologically, consistent with a failure in normal neuroepithelial homeostasis.MethodsAccordingly, we have focused on identifying cellular and molecular changes in presbyosmic OE. The study combined psychophysical testing with olfactory mucosa biopsy analysis, single-cell RNA-Sequencing (scRNA-Seq), and culture studies.ResultsWe identified evidence for inflammation-associated changes in the OE stem cells of presbyosmic patients. The presbyosmic basal stem cells exhibited increased expression of genes involved in response to cytokines or stress or the regulation of proliferation and differentiation. Using a culture model, we found that cytokine exposure drove increased TP63, a transcription factor acting to prevent OE stem cell differentiation.ConclusionsOur data suggest aging-related inflammatory changes in OE stem cells may contribute to presbyosmia via the disruption of normal epithelial homeostasis. OE stem cells may represent a therapeutic target for restoration of olfaction.FundingNIH grants DC018371, NS121067, DC016224; Office of Physician-Scientist Development, Burroughs-Wellcome Fund Research Fellowship for Medical Students Award, Duke University School of Medicine.

Recovery of Altered Diabetic Myofibroblast Heterogeneity and Gene Expression Are Associated with CD301b+ Macrophages

Diabetic wound healing is associated with impaired function and reduced numbers of myofibroblasts, a heterogeneous cell population with varying capacities to promote repair. To determine how diabetes alters myofibroblast composition, we performed flow cytometry and spatial tissue analysis of myofibroblast subsets throughout the healing process in diabetic (db/db) and control (db/+) mouse skin. We observed reduced numbers of profibrotic SCA1+; CD34+; CD26+ myofibroblasts in diabetic wounds five days after injury, with decreased expression of fibrosis-associated genes compared to myofibroblasts from db/+ mouse wounds. While the abundance of myofibroblasts remained reduced in db/db mouse wounds compared to controls, the altered myofibroblast heterogeneity and gene expression in diabetic mice was improved seven days after injury. The natural correction of myofibroblast composition and gene expression in db/db wound beds temporally corresponds with a macrophage phenotypic switch. Correlation analysis from individual wound beds revealed that wound healing in control mice is associated with CD206+ macrophages, while the rescued myofibroblast phenotypes in diabetic wounds are correlated with increased CD301b+ macrophage numbers. These data demonstrate how diabetes impacts specific subsets of myofibroblasts and indicate that signaling capable of rescuing impaired diabetic wound healing could be different from signals that regulate wound healing under nonpathological conditions.

Functional characterization of an interleukin 20 like homologue in grass carp Ctenopharyngodon idella

IL-20 is a pleiotropic cytokine that belongs to the IL-10 family and plays an important biological role in tissue homeostasis and regulation of host immune defenses. IL-20 homologues have recently been discovered in fish, but their functions have not been studied. In this study, an IL-20 like (IL-20L) cytokine was cloned in grass carp (Ctenopharyngodon idella) and its bioactivities were investigated. Expression analysis showed that the CiIL-20L gene was constitutively expressed in tissues with the highest expression detected in the head kidney. It was upregulated in the head kidney after infection with Flavobactrium columnare (F. cloumnare) and grass carp reovirus II (GCRV II). The recombinant CiIL-20L produced in E. coli cells was shown to be effective in inducing the expression of Th cytokine genes (IFN-γ, IL-4/13A, IL-4/13B and IL-10), macrophage marker genes (arginase 2, IRF4, KLF4 and SOCS3) and inflammatory genes (IL-1β, IL-6, IL-8 and TNFα) in the head kidney leukocytes when stimulated at 12 h. Long term culture (6 days) of head kidney macrophages in the presence of CiIL-20L leads to high expression of IRF4, TGFβ1 and arginase 2. Our data suggest that IL-20 may play regulatory roles in promoting Th responses, macrophage differentiation and inflammation.

Identification of an IL-22-Dependent Gene Signature as a Pharmacodynamic Biomarker

Interleukin-22 (IL-22) plays a role in epithelial barrier function and repair, and may provide benefits in conditions like inflammatory bowel disease. However, limited human data are available to assess the clinical effect of IL-22 administration. This study used a human intestinal cell line to identify an IL-22-dependent gene signature that could serve as a pharmacodynamic biomarker for IL-22 therapy. The response to IL-22Fc (UTTR1147A, an Fc-stabilized version of IL-22) was assessed in HT-29 cells by microarray, and the selected responsive genes were confirmed by qPCR. HT-29 cells demonstrated dose-dependent increases in STAT3 phosphorylation and multiple gene expression changes in response to UTTR1147A. Genes were selected that were upregulated by UTTR1147A, but to a lesser extent by IL-6, which also signals via STAT3. IL-1R1 was highly upregulated by UTTR1147A, and differential gene expression patterns were observed in response to IL-22Fc in the presence of IL-1β. An IL-22-dependent gene signature was identified that could serve as a pharmacodynamic biomarker in intestinal biopsies to support the clinical development of an IL-22 therapeutic. The differential gene expression pattern in the presence of IL-1β suggests that an inflammatory cytokine milieu in the disease setting could influence the clinical responses to IL-22.

Current knowledge of immunomodulation strategies for chronic skin wound repair

In orchestrating the wound healing process, the immune system plays a critical role. Hence, controlling the immune system to repair skin defects is an attractive approach. The highly complex immune system includes the coordinated actions of several immune cells, which can produce various inflammatory and antiinflammatory cytokines and affect the healing of skin wounds. This process can be optimized using biomaterials, bioactive molecules, and cell delivery. The present review discusses various immunomodulation strategies for supporting the healing of chronic wounds. In this regard, following the evolution of the immune system and its role in the wound healing mechanism, the interaction between the extracellular mechanism and immune cells for acceleration wound healing will be firstly investigated. Consequently, the immune-based chronic wounds will be briefly examined and the mechanism of progression, and conventional methods of their treatment are evaluated. In the following, various biomaterials-based immunomodulation strategies are introduced to stimulate and control the immune system to treat and regenerate skin defects. Other effective methods of controlling the immune system in wound healing which is the release of bioactive agents (such as antiinflammatory, antigens, and immunomodulators) and stem cell therapy at the site of injury are reviewed.

A systematic CRISPR screen reveals an IL-20/IL20RA-mediated immune crosstalk to prevent the ovarian cancer metastasis

Transcoelomic spread of cancer cells across the peritoneal cavity occurs in most initially diagnosed ovarian cancer (OC) patients and accounts for most cancer-related death. However, how OC cells interact with peritoneal stromal cells to evade the immune surveillance remains largely unexplored. Here, through an in vivo genome-wide CRISPR/Cas9 screen, we identified IL20RA, which decreased dramatically in OC patients during peritoneal metastasis, as a key factor preventing the transcoelomic metastasis of OC. Reconstitution of IL20RA in highly metastatic OC cells greatly suppresses the transcoelomic metastasis. OC cells, when disseminate into the peritoneal cavity, greatly induce peritoneum mesothelial cells to express IL-20 and IL-24, which in turn activate the IL20RA downstream signaling in OC cells to produce mature IL-18, eventually resulting in the polarization of macrophages into the M1-like subtype to clear the cancer cells. Thus, we show an IL-20/IL20RA-mediated crosstalk between OC and mesothelial cells that supports a metastasis-repressing immune microenvironment.

Maintenance of Barrier Tissue Integrity by Unconventional Lymphocytes

Mucosal surfaces, as a first barrier with the environment are especially susceptible to damage from both pathogens and physical trauma. Thus, these sites require tightly regulated repair programs to maintain barrier function in the face of such insults. Barrier sites are also enriched for unconventional lymphocytes, which lack rearranged antigen receptors or express only a limited range of such receptors, such as ILCs (Innate Lymphoid Cells), γδ T Cells and MAIT (Mucosal-Associated Invariant T Cells). Recent studies have uncovered critical roles for unconventional lymphocytes in regulating mucosal barrier function, and, in particular, have highlighted their important involvement in barrier repair. The production of growth factors such as amphiregulin by ILC2, and fibroblast growth factors by γδ T cells have been shown to promote tissue repair at multiple barrier sites. Additionally, MAIT cells have been shown to exhibit pro-repair phenotypes and demonstrate microbiota-dependent promotion of murine skin healing. In this review we will discuss how immune responses at mucosal sites are controlled by unconventional lymphocytes and the ways in which these cells promote tissue repair to maintain barrier integrity in the skin, gut and lungs.

Bacteroides ovatus Promotes IL-22 Production and Reduces Trinitrobenzene Sulfonic Acid-Driven Colonic Inflammation

The intestinal microbiota influences the development and function of the mucosal immune system. However, the exact mechanisms by which commensal microbes modulate immunity is not clear. We previously demonstrated that commensal Bacteroides ovatus ATCC 8384 reduces mucosal inflammation. Herein, we aimed to identify immunomodulatory pathways employed by B. ovatus. In germ-free mice, mono-association with B. ovatus shifted the CD11b+/CD11c+ and CD103+/CD11c+ dendritic cell populations. Because indole compounds are known to modulate dendritic cells, B. ovatus cell-free supernatant was screened for tryptophan metabolites by liquid chromatography-tandem mass spectrometry and larger quantities of indole-3-acetic acid were detected. Analysis of cecal and fecal samples from germ-free and B. ovatus mono-associated mice confirmed that B. ovatus could elevate indole-3-acetic acid concentrations in vivo. Indole metabolites have previously been shown to stimulate immune cells to secrete the reparative cytokine IL-22. Addition of B. ovatus cell-free supernatant to immature bone marrow-derived dendritic cells stimulated IL-22 secretion. The ability of IL-22 to drive repair in the intestinal epithelium was confirmed using a physiologically relevant human intestinal enteroid model. Finally, B. ovatus shifted the immune cell populations in trinitrobenzene sulfonic acid-treated mice and up-regulated colonic IL-22 expression, effects that correlated with decreased inflammation. Our data suggest that B. ovatus-produced indole-3-acetic acid promotes IL-22 production by immune cells, yielding beneficial effects on colitis.

Microenvironment Influence of a Novel Bioengineered Wound Product, APIS®: A Preliminary In Vitro Analysis of Inflammatory Marker and Growth Factor Secretion

Objective

Preliminary biological activity assessment of a novel bioengineered wound product (APIS®, SweetBio, Inc., Memphis, TN, USA), a synthesis of gelatin, Manuka honey, and hydroxyapatite, with in vitro indications to protect, instill balance to, and progress the wound microenvironment. Approach. The biological activity the bioengineered wound product (BWP) elicits on human cells in vitro was assessed by evaluating matrix metalloproteinase- (MMP-) related proteins expressed by macrophages and secretion of growth factors in fibroblasts. Cells were cultured with no treatment, stimulated with lipopolysaccharides (LPS), or seeded directly on the BWP for 24 hours. An additional 72-hour time point for the BWP was assessed to determine if the BWP maintained its activity compared to itself at 24 hours. Cell culture supernatants were assayed to quantify secreted protein levels.

Results

MMP-9 secretion from macrophages seeded on the BWP were nondetectable (P < 0.01), while a tissue inhibitor of MMP (TIMP-1) was detected. This decreased the overall MMP-9/TIMP-1 ratio secreted from macrophages seeded on the BWP compared to the controls. Additionally, the secretion of prohealing growth factors such as basic fibroblast growth factor (FGFb) and vascular endothelial growth factor (VEGF) was observed.

Conclusion

Results from this preliminary in vitro evaluation suggest that the BWP has the potential to instill balance to the wound microenvironment by reducing the MMP-9/TIMP-1 ratio secretion from macrophages and progress previously stalled chronic wounds towards healing by triggering the release of growth factors from fibroblasts.

Plant production and functional characterization of catfish interleukin-22 as a natural immune stimulant for aquaculture fish

As the world population increases and wild caught fisheries decline, aquaculture offers a sustainable solution addressing this global challenge. However, disease management remains difficult. With limited options, there is a need for innovative solutions. The cytokine interleukin-22 (IL-22) has emerged as a possible therapeutic target for fish and has been correlated with protection under pathogen challenge. Plant-based production systems have the potential to effectively manufacture and bring unique efficacy-enhancing features to the aquaculture industry; namely, the advantages of low cost for this commodity market, ready scalability, and reduced environmental impact. Catfish IL-22 produced at significant yield and purity highlights the use of plants as a promising production platform for therapeutic proteins with utility to the aquaculture industry. Purified cfIL-22 shows similar in vitro bioactivity to its mammalian homolog that include increased proliferation of catfish cells highlighting the tissue preservation capabilities associated with this protein. Recombinant cfIL-22 also upregulated expression of genes encoding a tissue repair protein, fibronectin, an antimicrobial peptide, Natural killer lysin-1, and a common innate immune protein, interferon. These findings support plant-made recombinant catfish interleukin-22 as a potential therapeutic for the aquaculture industry and further analysis of this protein for promoting animal health.

An update on potential biomarkers for diagnosing diabetic foot ulcer at early stage

As one of major chronic complications of diabetes, diabetic foot ulcer (DFU) is the main cause of disability and death. The clinical diagnosis and prognosis of DFU is inadequate. For clinicians, if the risk stratification of DFU can be obtained earlier in diabetic patients, the hospitalization, disability and mortality rate will be reduced. In addition to the inflammatory biomarkers that have been widely concerned and used, e.g., procalcitonin, pentraxin-3, C-reactive protein (CRP), interleukins (ILs), and tumor necrosis factor-α (TNF-α), etc., a more comprehensive prediction of the risk and severity of DFU is needed to reflect new biomarkers for therapeutic intervention effects. Along with the development of systems biology technology, genomics, proteomics, metabolomics and microbiome have been used in the studies on DFU for better understanding of the disease. In this review, new biomarkers that are expected to assist in the accurate diagnosis and risk stratification of DFU will be discussed and summarized in detail.

Human adipose mesenchymal stem cells modulate myeloid cells toward an anti-inflammatory and reparative phenotype: role of IL-6 and PGE2

BACKGROUND

Mesenchymal stem cells (MSCs) activate the endogenous immune regulatory system, inducing a therapeutic effect in recipients. MSCs have demonstrated the ability to modulate the differentiation of myeloid cells toward a phagocytic and anti-inflammatory profile. Allogeneic, adipose-derived MSCs (ASCs) have been investigated for the management of complex perianal fistula, with darvadstrocel being the first ASC therapy approved in Europe in March 2018. Additionally, ASCs are being explored as a potential treatment in other indications. Yet, despite these clinical advances, their mechanism of action is only partially understood.

METHODS

Freshly isolated human monocytes from the peripheral blood were differentiated in vitro toward M0 non-polarized macrophages (Mphs), M1 pro-inflammatory Mphs, M2 anti-inflammatory Mphs, or mature dendritic cells (mDCs) in the presence or absence of ASCs, in non-contact conditions. The phenotype and function of the differentiated myeloid populations were determined by flow cytometry, and their secretome was analyzed by OLINK technology. We also investigated the capacity of ASCs to modulate the phenotype and function of terminally differentiated M1 Mphs. The role of soluble factors interleukin (IL)-6 and prostaglandin E2 (PGE2) on the ability of ASCs to modulate myeloid cells was assessed using neutralization assays, CRISPR/Cas9 knock-down of cyclooxygenase 2 (COX-2), and ASC-conditioned medium assays using pro-inflammatory stimulus.

RESULTS

Co-culture of monocytes in the presence of ASCs resulted in the polarization of Mphs and mDCs toward an anti-inflammatory and phagocytic phenotype. This was characterized by an increase in phagocytic receptors on the cell surface of Mphs (M0, M1, and M2) and mDCs, as well as modulation of chemokine receptors and reduced expression of pro-inflammatory, co-stimulatory molecules. ASCs also modulated the secretome of Mphs and mDCs, demonstrated by reduced expression of pro-inflammatory factors and increased expression of anti-inflammatory and reparative factors. Chemical inhibition of PGE2 with indomethacin abolished this modulatory effect, whereas treatment with a neutralizing anti-IL-6 antibody resulted in a partial abolishment. The knock-down of COX-2 in ASCs and the use of IL-1β-activated ASC-conditioned media confirmed the key role of PGE2 in ASC-mediated myeloid modulation. In our in vitro experimental settings, ASCs failed to modulate the phenotype and function of terminally polarized M1 Mphs.

CONCLUSIONS

The results demonstrate that ASCs are able to modulate the in vitro differentiation of myeloid cells toward an anti-inflammatory and reparative profile. This modulatory effect was mediated mainly by PGE2 and, to a lesser extent, IL-6.

A Double Edged Sword Role of Interleukin-22 in Wound Healing and Tissue Regeneration

Wound healing and tissue regeneration is an intricate biological process that involves repair of cellular damage and maintenance of tissue integrity. Cascades involved in wound healing and tissue regeneration highly overlap with cancer causing pathways. Usually, subsequent tissue damage events include release of a number of cytokines to accomplish post-trauma restoration. IL-22 is one of the cytokines that are immediately produced to initiate immune response against several tissue impairments. IL-22 is a fundamental mediator in inflammation, mucous production, protective role against pathogens, wound healing, and tissue regeneration. However, accumulating evidence suggests pivotal role of IL-22 in instigation of various cancers due to its pro-inflammatory and tissue repairing activity. In this review, we summarize how healing effects of IL-22, when executed in an uncontrollable fashion can lead to carcinogenesis.

Bicontinuous microemulsions containing Melaleuca alternifolia essential oil as a therapeutic agent for cutaneous wound healing

The Melaleuca alternifolia essential oil (MEO) has been widely used due to its healing and antimicrobial action. Its incorporation into drug delivery systems is a reality, and numerous studies have already been developed for this purpose. In this regard, the aim of this work was to develop, characterize, and evaluate the in vivo pharmacological activity of bicontinuous microemulsions (BME) containing MEO. Through diagram construction, a formulation consisting of Kolliphor® HS 15 (31.05%), Span® 80 (3.45%), isopropyl myristate (34.5%), and distilled water (31%) was selected and MEO was incorporated in the proportion of 3.45% (v/v). Morphological analysis characterization confirms that the system studied herein is a BME. The evaluated formulation showed physicochemical characteristics that allow its topical use. Rheologically, samples were characterized as pseudo-plastic non-Newtonian thixotropic fluids. The chromatographic method developed is in accordance with the current recommendations. The extraction method used assured a 100% recovery of the pharmacological marker (terpinen-4-ol). In vivo studies suggest that BME loaded with MEO may contribute to the healing process of skin wounds. In addition, it demonstrated antibacterial activity for Gram-positive and Gram-negative bacteria. Therefore, the BME system loaded with MEO is promising as a healing and antimicrobial agent for skin wounds.Graphical abstract.

IL-24: A new player in the pathogenesis of pro-inflammatory and allergic skin diseases

Interleukin (IL)-24 is a member of the IL-20 family of cytokines and is produced by various types of cells, such as CD4⁺ T cells, NK cells, mast cells, keratinocytes, bronchial epithelial cells, and myofibroblasts. Previous studies suggest that IL-24 plays an essential role in the pathogenesis of pro-inflammatory autoimmune disorders such as psoriasis, arthritis, and inflammatory bowel diseases. However, the role of IL-24 in the pathogenesis of allergic diseases has been elusive. It has already been reported that IL-24 is involved in the pathogenesis of allergic lung and skin diseases. Moreover, we have recently revealed for the first time the pivotal functions of IL-24 in IL-13-mediated skin barrier dysfunction in atopic dermatitis (AD), which is known to be a characteristic of AD caused by Th2 cytokines such as IL-4 or IL-13. In this review, we show recent advances in the basic characteristics of IL-24 and its novel functions in the pathogenesis of allergic skin inflammation, focusing on AD. A better understanding of the role of IL-24 in allergic diseases can lead to the development of new therapeutic options.

Characterization of IL-19, -20, and -24 in acute and chronic kidney diseases reveals a pro-fibrotic role of IL-24

BACKGROUND

Recently, the role of IL-19, IL-20 and IL-24 has been reported in renal disorders. However, still little is known about their biological role.

METHODS

Localization of IL-20RB was determined in human biopsies and in the kidneys of mice that underwent unilateral ureteral obstruction (UUO). Renal Il19, Il20 and Il24 expression was determined in ischemia/reperfusion, lipopolysaccharide, streptozotocin, or UUO induced animal models of kidney diseases. The effects of H₂O₂, LPS, TGF-β1, PDGF-B and IL-1β on IL19, IL20 and IL24 expression was determined in peripheral blood mononuclear cells (PBMCs). The extents of extracellular matrix (ECM) and α-SMA, Tgfb1, Pdgfb, and Ctgf expression were determined in the kidneys of Il20rb knockout (KO) and wild type (WT) mice following UUO. The effect of IL-24 was also examined on HK-2 tubular epithelial cells and NRK49F renal fibroblasts.

RESULTS

IL-20RB was present in the renal biopsies of patients with lupus nephritis, IgA and diabetic nephropathy. Amount of IL-20RB increased in the kidneys of mice underwent UUO. The expression of Il19, Il20 and Il24 increased in the animal models of various kidney diseases. IL-1β, H₂O₂ and LPS induced the IL19, IL20 and IL24 expression of PBMCs. The extent of ECM, α-SMA, fibronectin, Tgfb1, Pdgfb, and Ctgf expression was lower in the kidney of Il20rb KO compared to WT mice following UUO. IL-24 treatment induced the apoptosis and TGF-β1, PDGF-B, CTGF expression of HK-2 cells.

CONCLUSIONS

Our data confirmed the significance of IL-19, IL-20 and IL-24 in the pathomechanism of renal diseases. Furthermore, we were the first to demonstrate the pro-fibrotic effect of IL-24.

Macrophage mediation in normal and diabetic wound healing responses

PURPOSE

The failure in timely healing of wounds is a central feature in chronic wounds that leads to physiological, psychological and economic burdens. Macrophages have been demonstrated to have various functions in wounds including host defense, the promotion and resolution of inflammation, the removal of apoptotic cells and tissue restoration following injury. Accumulated evidence suggests that macrophage dysfunction is a component of the pathogenesis of non-healing wounds. While the overall signaling cascades have been well understood, their complex interplay and a detailed characterization of events that are disrupted in chronic wounds have still not emerged satisfactorily.

METHODS

The existing literature was reviewed to summarize the regulation of macrophage polarization in wound closure and dysregulation in non-healing wounds. Further, the review also underscored the role of Nrf2 in promoting macrophage-mediated regulation in wound responses and in particular, macrophage involvement in iron homeostasis that is impaired in chronic wounds such as in diabetes.

RESULTS

The mechanisms involved in the reprogramming of macrophage subtypes in chronic wounds are still emerging. Furthermore, treating non-healing wounds has increasingly been shifting focus from generic treatments to the development of targeted therapies. Increasing evidence suggests the need for modeling wound tissue in vitro which may very well serve a critical aspect to characterize the relevant factors that sustain chronic wounds in vivo such as the constant iron overload at the wound site from recurrent infection and bleeding.

CONCLUSION

The development of targeted therapies and also developing a reliable means to monitor assisted healing of chronic wounds are two major goals to be pursued. In addition, identifying molecular targets that can regulate macrophages to aid tissue restoration in chronic wounds would serve the crucial step in realizing both aforementioned goals.

Assessment of T helper 17-associated cytokines in thromboangiitis obliterans

Background

The management of thromboangiitis obliterans (TAO) remains a medical challenge because of its unknown etiology. It is also not known whether it is a systemic or localized disease or a type of autoimmune vasculitis.

Methods

In this study, we evaluated the serum level of IL-17 and IL-23 which increase in both systemic inflammation and autoimmunity, in 60 TAO patients and 30 age- and smoking habit-matched controls. Also, IL-22, which has reported high level during infection but not in autoimmunity, was evaluated.

Results

The serum levels of IL-17, IL-22 and IL-23 were significantly higher in the TAO patients in comparison with the controls (P<0.001). Notably, the serum levels of IL-17, IL-22 and IL-23 were highest in the patients with the chief complaint of chronic ulcer and lowest in the patients with gangrene (P<0.05). Also, the serum level of IL-22 was significantly higher in the anemic patients in comparison with the non-anemic patients (P=0.03).

Conclusion

Owing to our findings, TAO appears more likely to be a systemic disorder rather than a localized vasculopathy. Therefore, treatment protocols based on systemic treatment of TAO patients may be more helpful than localized treatment, such as bypass surgery and endovascular procedures. Also, according to our findings regarding the high level of IL-22, the trigger of TAO development may be an infectious pathogen. However, additional research is highly recommended to investigate whether TAO is an infectious disease or an infectious-induced autoimmunity.

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Interleukin (IL)-22 from IL-20 Subfamily of Cytokines Induces Colonic Epithelial Cell Proliferation Predominantly through ERK1/2 Pathway

The interleukin (IL)-20 subfamily of cytokines consists of IL-19, IL-20, IL-22, IL-24, and IL-26, and the expression of IL-20, IL-22, and IL-24 is reported to be higher in the colon of patients with ulcerative colitis. Although the receptors for these cytokines are highly expressed in the colon epithelium, their effects on epithelial renewal are not clearly understood. This study evaluated the effects of IL-20, IL-22, and IL-24 in epithelial renewal using the LS174T human colon cancer epithelial cell line. LS174T cells were treated with IL-20, IL-22, and IL-24 (25, 50, and 100 ng/mL) and a live-cell imaging system was used to evaluate the effects on cell proliferation. Following treatment, the signaling pathways contributing to cell proliferation were investigated through Western blotting in LS174T cells and downstream transcriptional changes through qRT-PCR in LS174T cells, and RNA-Seq in primary murine intestinal epithelial cells. Our results demonstrated that only IL-22 promoted LS174T cell proliferation, mediated via extracellular-signal-regulated kinase (ERK)1/2-mediated downstream regulation of p90RSK, c-Jun, and transcriptional changes of TRIM15 and STOM. IL-22 also promoted expression of ERK1/2-independent genes such as DDR2, LCN2, and LRG1, which are known to be involved in cell proliferation and migration. This study suggests that IL-22 induces cell proliferation in highly proliferative cells such as intestinal epithelial cells.

Role of growth factors and cytokines in diabetic foot ulcer healing: A detailed review

The aim of the review is to examine the role of growth factors and cytokines in the management of Diabetic Foot Ulcers, such as platelet derived growth factor (PDGF), vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF) and Insulin like growth factor (IGF). Taking this a step further, the role of Hypoxia-inducible factors (HIFs), Transforming growth factor beta 1 (TGF-β-1) and other growth factors have also been examined, with regard to the treatment of diabetic foot ulcers. The roles of these above-mentioned growth cytokines have been analyzed by studying various scholastic articles. The complete process of wound healing is implemented and regulated by numerous cytokines and human growth factors. The findings of the study indicate that wound healing of diabetic foot ulcers is a complex and extremely challenging biological and molecular process that involves coordinated efforts of multiple cell types. The therapeutic effects of various growth factors in the clinical management of wounds are chronic venous ulcers, pressure ulcers, and diabetic foot ulcers. It has been concluded that altercations of various cytokines are found in patients enduring diabetic foot ulcers. In a similar way, changes in the level of cytokines are also found in patients suffering from other diabetic complications such as diabetic nephropathy, retinopathy, and neuropathy. Subsequently, the diabetic wound healing process can be accelerated by regulating the levels of the cytokines.

IL-10 Family Cytokines IL-10 and IL-22: from Basic Science to Clinical Translation

Cytokines are among the most important effector and messenger molecules in the immune system. They profoundly participate in immune responses during infection and inflammation, protecting against or contributing to diseases such as allergy, autoimmunity, and cancer. Manipulating cytokine pathways, therefore, is one of the most effective strategies to treat various diseases. IL-10 family cytokines exert essential functions to maintain tissue homeostasis during infection and inflammation through restriction of excessive inflammatory responses, upregulation of innate immunity, and promotion of tissue repairing mechanisms. Their important functions in diseases are supported by data from many preclinical models, human genetic studies, and clinical interventions. Despite significant efforts, however, there is still no clinically approved therapy through manipulating IL-10 family cytokines. Here, we summarize the recent progress in understanding the biology of this family of cytokines, suggesting more specific strategies to maneuver these cytokines for the effective treatment of inflammatory diseases and cancers.

Targeting IL-10 Family Cytokines for the Treatment of Human Diseases

Members of the interleukin (IL)-10 family of cytokines play important roles in regulating immune responses during host defense but also in autoimmune disorders, inflammatory diseases, and cancer. Although IL-10 itself primarily acts on leukocytes and has potent immunosuppressive functions, other family members preferentially target nonimmune compartments, such as tissue epithelial cells, where they elicit innate defense mechanisms to control viral, bacterial, and fungal infections, protect tissue integrity, and promote tissue repair and regeneration. As cytokines are prime drug targets, IL-10 family cytokines provide great opportunities for the treatment of autoimmune diseases, tissue damage, and cancer. Yet no therapy in this space has been approved to date. Here, we summarize the diverse biology of the IL-10 family as it relates to human disease and review past and current strategies and challenges to target IL-10 family cytokines for clinical use.

Randomized Phase I Healthy Volunteer Study of UTTR1147A (IL-22Fc): A Potential Therapy for Epithelial Injury

Most treatments for epithelial injury target hematopoietic mechanisms, possibly causing immunosuppression. Interleukin (IL)-22 promotes tissue regeneration, acting directly on epithelial cells. UTTR1147A, a human IL-22Fc (immunoglobulin G (IgG)4) fusion protein, activates IL-22 signaling. This phase I placebo-controlled trial of single, ascending, i.v. (1-120 μg/kg) and s.c (3-120 μg/kg) doses of UTTR1147A analyzed its effects on safety, tolerability, pharmacokinetics, and pharmacodynamic biomarkers in healthy volunteers. Most adverse events (AEs) were mild or moderate. The maximum tolerated i.v. dose in healthy volunteers was 90 μg/kg. Predominant AEs were dose-dependent reversible skin effects consistent with IL-22 pharmacology. UTTR1147A exposure increased approximately dose-proportionally, with a half-life of ~1 week. IL-22 biomarkers (regenerating islet protein 3A (REG3A), serum amyloid A (SAA), and C-reactive protein (CRP)) increased dose-dependently. Neither inflammatory symptoms and signs nor cytokines increased with CRP elevations. UTTR1147A demonstrated acceptable safety, pharmacokinetics, and IL-22R engagement, supporting further clinical development.

Nonclinical safety assessment of a human interleukin-22FC IG fusion protein demonstrates in vitro to in vivo and cross-species translatability

Although Interleukin-22 (IL-22) is produced by various leukocytes, it preferentially targets cells with epithelial origins. IL-22 exerts essential roles in modulating various tissue epithelial functions, such as innate host defense against extracellular pathogens, barrier integrity, regeneration, and wound healing. Therefore, IL-22 is thought to have therapeutic potential in treating diseases associated with infection, tissue injury or chronic tissue damage. A number of in vitro and in vivo nonclinical studies were conducted to characterize the pharmacological activity and safety parameters of UTTR1147A, an IL-22 recombinant fusion protein that links the human cytokine IL-22 with the Fc portion of a human immunoglobulin. To assess the pharmacological activity of UTTR1147A, STAT3 activation was evaluated in primary hepatocytes isolated from human, cynomolgus monkey, minipig, rat, and mouse after incubation with UTTR1147A. UTTR1147A activated STAT3 in all species evaluated, demonstrating that all were appropriate nonclinical species for toxicology studies. The nonclinical safety profile of UTTR1147A was evaluated in rats, minipigs, and cynomolgus monkeys to establish a safe clinical starting dose for humans in Phase I trials and to support clinical intravenous, subcutaneous and/or topical administration treatment regimen. Results demonstrate the cross-species translatability of the biological response in activating the IL-22 pathway as well as the translatability of findings from in vitro to in vivo systems. UTTR1147A was well tolerated in all species tested and induced the expected pharmacologic effects of epidermal hyperplasia and a transient increase in on-target acute phase proteins. These effects were all considered to be clinically predictable, manageable, monitorable, and reversible.

Downregulation of IL-22 can be considered as a risk factor for onset of type 2 diabetes

There is some controversy as for the roles played by tumor growth factor-β (TGF-β), interleukin-1β (IL-1β), and IL-22 in the onset process of type 2 diabetes (T2D). The main aim of this project was to examine serum levels of TGF-β, IL-1β, and IL-22 in the new cases and long period T2D patients as well as healthy controls. In this study, 115 new T2D patient cases (group 1), 434 T2D patients who have suffered from the disease more than 2 years (group 2), and 104 healthy controls have been selected from 6240 (3619 females) patients who were under study population from Kerman Coronary Artery Disease Risk Factor Study. Serum levels of TGF-β, IL-1β, and IL-22 have been evaluated using commercial kits. Serum levels of TGF-β and IL-1β significantly increased, while IL-22 decreased in 2 groups in comparison to healthy controls. Serum levels of IL-22, but not TGF-β and IL-1β, were significantly decreased in group 1 in comparison to healthy controls. There were no significant differences between groups 1 and 2 as for the cytokine levels. Serum levels of IL-22 increased in the females in group 2 when compared to females in group 1. It appears that TGF-β and IL-1β participate in the induction of inflammation after establishment of T2D, while decrease in IL-22 may be considered as a key factor for onset of the disease. Gender can also be considered as the main risk factor for variation in cytokine levels.