Effects of Granulocyte-Macrophage Colony-Stimulating (GM-CSF) Factor on Corneal Epithelial Cells in Corneal Wound Healing Model

Characterization of Inflammatory Mediators and Metabolome in Interstitial Fluid Collected with Dermal Open Flow Microperfusion before and at the End of Dupilumab Treatment in Atopic Dermatitis

Dupilumab is a monoclonal antibody approved for the treatment of atopic dermatitis (AD); however, its effects on molecular, cellular, and immunological levels remain to be elucidated. In this study, blood and dermal interstitial fluid (ISF) from nonlesional (NL) and lesional (L) skin were collected from eight patients with moderate to severe AD, before (visit 2-v2) and at the end of a 16-week treatment with dupilumab (visit 10-v10). Clinical treatment effect was demonstrated by significantly decreased AD severity scores at the end of treatment. At v10 versus v2, the percentages of CD4+ interleukin-producing cells showed a decreasing trend in ISF L and NL, unbound IL-4 levels in plasma were increased, IL-5 levels in ISF L reduced, and levels of factors involved in anti-inflammatory pathways and re-epithelization increased. At v2, ISF L showed that AD lesions might have altered amino acid pathways and lipid signaling compared to ISF NL. At v10, ISF L exhibited raised levels of long- and very-long-chain fatty acids and lipids compared to v2. Furthermore, dupilumab administration caused reduced expression of miR-155-5p and miR-378a-3p in ISF L. In conclusion, results from the present study provided novel knowledge by linking local immune and metabolic alterations to AD pathogenesis and treatment response.

Effects of Recombinant Human Granulocyte/Macrophage Colony-Stimulating Factor on Diabetic Lower Extremity Ulcers: Case Series of Nine Patients

Background

Diabetic lower extremity ulcer, including diabetic foot ulcer (DFU) and leg ulcer, is one of the refractory complications of diabetes, the treatment of which is challenging, expensive, and lengthy. Recombinant Human Granulocyte/Macrophage Colony-stimulating Factor (rhGM-CSF) is an immunomodulatory cytokine that has been mainly applied in the treatment of hematological diseases. Clinical evidence regarding GM-CSF in the treatment of diabetic lower extremity ulcers is limited. This study is the first case series that investigates the repurpose effects of rhGM-CSF on diabetic ulcer healing in real clinical practice.

Methods

Nine patients diagnosed with diabetes and refractory lower extremity ulcer (ulcer duration ≥2 weeks) were included from September 2021 to February 2023 in the Division of Endocrinology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology. Patients with Wagner grade ≥4 and SINDAD ≥5 were excluded. The included subjects were treated with rhGM-CSF plus standard of care (SOC) including glycemic control, foot care education, debridement of necrotic tissues, topical wound dressings, offloading, and infection control when necessary. The observation endpoint was complete epithelialization. Their clinical manifestations, laboratory tests, and therapeutic effects were extracted and analyzed.

Results

The case series included 9 cases aged from 29 to 80 years and all the patients were male. Seven of 9 patients presented neuropathic ulcer. Only one case showed non-infected ulcer from tissue samples and one case presented ankle brachial index (ABI) <0.9. It was observed that the ulcer areas among these 9 patients gradually declined throughout the whole treatment period with the average healing velocity 0.32 ± 013 cm2/day and the mean time to complete healing 16.0 ± 3.7 days. The relative area (percentage of initial ulcer area) decreased to 66.7 ± 13.0% on average after the first treatment. Ulcers in all the 9 patients achieved complete epithelialization after 4-8 times treatments.

Conclusion

The case series suggests rhGM-CSF as a promising therapeutic strategy for the treatment of diabetic ulceration. More robust data from randomized controlled trials are required to further evaluate its clinical efficacy.

Unique cytokine signature in ocular Stevens-Johnson syndrome non-responders

PURPOSE

To clinically define a subset of patients with chronic ocular Stevens-Johnson syndrome non-responders (SJS-NR) and analyze their cytokine profile compared to clinical responders (SJS-CR).

METHODS

A total of 32 SJS cases (n = 32, 64 eyes) managed over a period of three years were segregated into clinical responders (n = 24, 48 eyes) and non-responders (n = 8, 16 eyes). Cases were determined as non-responders based on persistent, refractory, and non-mechanical inflammation of the conjunctiva. Age- and sex-matched healthy controls (n = 25, 50 eyes) were recruited. Tear specimens collected using Schirmer's strip were profiled for 27 cytokines using an immunoassay-based 27-bioplex array.

RESULTS

Tear cytokine profiling revealed 18 cytokines to be differentially expressed in SJS-NR compared to SJS-CR. While PDGF-BB, IL-4, IL-1β, VEGF, IL-12p70, IFN-γ, IL-9, and IL-1RA were upregulated, GM-CSF, eotaxin, IP-10, IL-10, MCP-1, G-CSF, IL-6, IL-13, and bFGF were downregulated in SJS-NR compared to SJS-CR. The cytokines IL-13, IL-10, and IP-10 were decreased in both SJS-NR and SJS-CR compared to controls.

CONCLUSION

The inflammation in SJS-NR continues to worsen despite the correction of mechanical causes, resulting in progressive deterioration of the cornea. The cytokine profile of SJS-NR was remarkably different from that of SJS-CR, indicating a T helper 2-type protective proliferative response and an impaired migratory potential of the conjunctival epithelium. These factors could possibly lead to poor healing of the corneal epithelium in a markedly pro-inflammatory and pro-angiogenic milieu. The top four differentially expressed cytokines, PDGF-BB, IL-4, IL-10, and IL-6, are proposed as potential biomarkers of SJS-NR.

Topically-applied collagen-binding serum albumin-fused interleukin-4 modulates wound microenvironment in non-healing wounds

Non-healing wounds have a negative impact on quality of life and account for many cases of amputation and even early death among patients. Diabetic patients are the predominate population affected by these non-healing wounds. Despite the significant clinical demand, treatment with biologics has not broadly impacted clinical care. Interleukin-4 (IL-4) is a potent modulator of the immune system, capable of skewing macrophages towards a pro-regeneration phenotype (M2) and promoting angiogenesis, but can be toxic after frequent administration and is limited by its short half-life and low bioavailability. Here, we demonstrate the design and characterization of an engineered recombinant interleukin-4 construct. We utilize this collagen-binding, serum albumin-fused IL-4 variant (CBD-SA-IL-4) delivered in a hyaluronic acid (HA)-based gel for localized application of IL-4 to dermal wounds in a type 2 diabetic mouse model known for poor healing as proof-of-concept for improved tissue repair. Our studies indicate that CBD-SA-IL-4 is retained within the wound and can modulate the wound microenvironment through induction of M2 macrophages and angiogenesis. CBD-SA-IL-4 treatment significantly accelerated wound healing compared to native IL-4 and HA vehicle treatment without inducing systemic side effects. This CBD-SA-IL-4 construct can address the underlying immune dysfunction present in the non-healing wound, leading to more effective tissue healing in the clinic.

An in vitro comparison of human corneal epithelial cell activity and inflammatory response on differently designed ocular amniotic membranes and a clinical case study

Amniotic membrane (AM) is a naturally derived biomaterial with biological and mechanical properties important to Ophthalmology. The epithelial side of the AM promotes epithelialization, while the stromal side regulates inflammation. However, not all AMs are equal. AMs undergo different processing with resultant changes in cellular content and structure. This study evaluates the effects of sidedness and processing on human corneal epithelial cell (HCEC) activity, the effect of processing on HCEC inflammatory response, and then a case study is presented. Three differently processed, commercially available ocular AMs were selected: (1) Biovance®3L Ocular, a decellularized, dehydrated human AM (DDHAM), (2) AMBIO2®, a dehydrated human AM (DHAM), and (3) AmnioGraft®, a cryopreserved human AM (CHAM). HCECs were seeded onto the AMs and incubated for 1, 4 and 7 days. Cell adhesion and viability were evaluated using alamarBlue assay. HCEC migration was evaluated using a scratch wound assay. An inflammatory response was induced by TNF-α treatment. The effect of AM on the expression of pro-inflammatory genes in HCECs was compared using quantitative polymerase chain reaction (qPCR). Staining confirmed complete decellularization and the absence of nuclei in DDHAM. HCEC activity was best supported on the stromal side of DDHAM. Under inflammatory stimulation, DDHAM promoted a higher initial inflammatory response with a declining trend across time. Clinically, DDHAM was used to successfully treat anterior basement membrane dystrophy. Compared with DHAM and CHAM, DDHAM had significant positive effects on the cellular activities of HCECs in vitro, which may suggest greater ocular cell compatibility in vivo.

Scaffold-Free Strategy Using a PEG-Dextran Aqueous Two-Phase-System for Corneal Tissue Repair

Forming thin tissue constructs with minimal extracellular matrix surrounding them is important for tissue engineering applications. Here, we explore and optimize a strategy that enables rapid fabrication of scaffold-free corneal tissue constructs using the liquid-liquid interface of an aqueous two-phase system (ATPS) that is based on biocompatible polymers, dextran and polyethylene glycol. Intact tissue-like constructs, made of corneal epithelial or endothelial cells, can be formed on the interface between the two liquid phases of ATPS within hours and subsequently collected simply by removing the liquid phases. The formed corneal cell constructs express essential physiological markers and have preserved viability and proliferative ability in vitro. The corneal epithelial cell constructs are also able to re-epithelialize the corneal epithelial wound in vitro. The results suggest the promise of our reported strategy in corneal repair.

Knockdown expression of a MYB-related transcription factor gene, OsMYBS2, enhances production of recombinant proteins in rice suspension cells

BACKGROUND

Transgenic plant suspension cells show economic potential for the production of valuable bioproducts. The sugar starvation-inducible rice αAmy3 promoter, together with its signal peptide, is widely applied to produce recombinant proteins in rice suspension cells. The OsMYBS2 transcription factor was shown recently to reduce activation of the αAmy3 promoter by competing for the binding site of the TA box of the αAmy3 promoter with the potent OsMYBS1 activator. In this study, rice suspension cells were genetically engineered to silence OsMYBS2 to enhance the production of recombinant proteins.

RESULTS

The mouse granulocyte-macrophage colony-stimulating factor (mGM-CSF) gene was controlled by the αAmy3 promoter and expressed in OsMYBS2-silenced transgenic rice suspension cells. Transcript levels of the endogenous αAmy3 and the transgene mGM-CSF were increased in the OsMYBS2-silenced suspension cells. The highest yield of recombinant mGM-CSF protein attained in the OsMYBS2-silenced transgenic suspension cells was 69.8 µg/mL, which is 2.5-fold that of non-silenced control cells. The yield of recombinant mGM-CSF was further increased to 118.8 µg/mL in cultured cells derived from homozygous F₅ seeds, which was 5.1 times higher than that of the control suspension cell line.

CONCLUSIONS

Our results demonstrate that knockdown of the transcription factor gene OsMYBS2 increased the activity of the αAmy3 promoter and improved the yield of recombinant proteins secreted in rice cell suspension cultures.

Epidermal Growth Factor Receptor Expression in the Corneal Epithelium

A properly functioning cornea is critical to clear vision and healthy eyes. As the most anterior portion of the eye, it plays an essential role in refracting light onto the retina and as an anatomical barrier to the environment. Proper vision requires that all layers be properly formed and fully intact. In this article, we discuss the role of the epidermal growth factor receptor (EGFR) in maintaining and restoring the outermost layer of the cornea, the epithelium. It has been known for some time that the addition of epidermal growth factor (EGF) promotes the restoration of the corneal epithelium and patients using EGFR inhibitors as anti-cancer therapies are at increased risk of corneal erosions. However, the use of EGF in the clinic has been limited by downregulation of the receptor. More recent advances in EGFR signaling and trafficking in corneal epithelial cells have provided new insights in how to overcome receptor desensitization. We examine new strategies for overcoming the limitations of high ligand and receptor expression that alter trafficking of the ligand:receptor complex to sustain receptor signaling.

Growth Factors, Reactive Oxygen Species, and Metformin-Promoters of the Wound Healing Process in Burns?

Burns can be caused by various factors and have an increased risk of infection that can seriously delay the wound healing process. Chronic wounds caused by burns represent a major health problem. Wound healing is a complex process, orchestrated by cytokines, growth factors, prostaglandins, free radicals, clotting factors, and nitric oxide. Growth factors released during this process are involved in cell growth, proliferation, migration, and differentiation. Reactive oxygen species are released in acute and chronic burn injuries and play key roles in healing and regeneration. The main aim of this review is to present the roles of growth factors, reactive oxygen species, and metformin in the healing process of burn injuries.

The influence of a biofilm-dispersing wound gel on the wound healing process

Topical antimicrobials that reduce the bacterial bioburden within a chronically‐infected wound may have helpful or harmful effects on the healing process. We used murine models of full‐thickness skin wounds to determine the effects of the novel biofilm‐dispersing wound gel (BDWG) and its gel base on the healing of uninfected wounds. The rate of wound closure over 19 days was comparable among the BDWG‐treated (BT) wounds and the controls. Compared with the controls, histology of the BT wounds showed formation of a stable blood clot at day 1, more neovascularisation and reepithelialisation at day 3, and more organised healing at day 7. Fluorescence‐activated cell sorting analysis showed a lower percentage of neutrophils in wounded tissues of the BT group at days 1 and 3, and significantly more M2 macrophages at day 3. Levels of proinflammatory cytokines and chemokines were increased over the uninjured baseline within the wounds of all treatment groups but the levels were significantly lower in the BT group at day 1, modulating the inflammatory response. Our results suggest that BDWG does not interfere with the wound healing process and may enhance it by lowering inflammation and allowing transition to the proliferative stage of wound healing by day 3.

Effect and underlying mechanisms of airborne particulate matter 2.5 (PM2.5) on cultured human corneal epithelial cells

Health problems caused by airborne particulate matter with a diameter less than 2.5 (PM2.5), especially in the respiratory system, have become a worldwide problem, but the influence and mechanisms of PM2.5 on the ocular surface have not been sufficiently elucidated. We investigated in vitro the onset and pathogenesis of corneal damage induced by PM2.5. Two types of PM2.5 samples originating from Beijing (designated #28) and the Gobi Desert (designated #30) were added to the culture medium of immortalized cultured human corneal epithelial cells (HCECs) to examine the effects on survival rates, autophagy, and proinflammatory cytokine production. Both types of PM2.5 significantly reduced the HCEC survival rate in a concentration-dependent manner by triggering autophagy. In particular, compared with #30, #28 induced much more severe damage in HCECs. Physical contact between PM2.5 and HCECs was not a primary contributor to PM2.5-induced HCEC damage. Among the 38 proinflammatory cytokines examined in this study, significant increases in the granulocyte macrophage colony-stimulating factor (GM-CSF) and interleukin-6 levels and a significant reduction in the interleukin-8 level were detected in culture medium of PM2.5-exposed HCECs. Simultaneous addition of a GM-CSF inhibitor, suramin, alleviated the HCEC impairment induced by PM2.5. In conclusion, PM2.5 induces HCEC death by triggering autophagy. Some cytokines that are released from HCECs, including GM-CSF, may be involved in HCEC damage caused by PM2.5 exposure.

Histological study of the effect of granulocyte colony-stimulating factor on experimentally induced corneal burn in adult male albino rats

Chemical injuries to the eye represent one of the true ophthalmic emergencies that require immediate and intensive intervention to minimize severe complications and visual loss. Granulocyte colony-stimulating factor (G-CSF) is a potent hematopoietic cytokine that influences the proliferation, survival, maturation, and the functional activation of granulocytes. The present work was performed to evaluate the histological effect of G-CSF in treating rat corneal alkali burn model. Thirty adult male albino rats were divided equally into three main groups: Group I was served as a control group, and in Group II and III, their corneas of the right eyes were injured by applying a piece of filter paper soaked in 1M NaOH. Group II (alkali burn-induced group) was left without any treatment, while Group III (G-CSF-treated group) was injected subcutaneously by 100 µg/kg of G-CSF for 5 consecutive days. All animals were sacrificed after 3 weeks. Cornea specimens were processed for histological and immunohistochemical staining for P63 followed by morphometry. Microscopic examination of Group II revealed marked alterations in the corneal epithelium, inflammatory cellular infiltration, and neovascularization. Treatment with G-CSF showed great improvement of the corneal structure, disappearance of the neovascularization and the inflammatory cells, and decreased p63 reaction of the basal layers.

Regeneration and Repair of Skin Wounds: Various Strategies for Treatment

Skin as a mechanical barrier between the inner and outer environment of our body protects us against infection and electrolyte loss. This organ consists of 3 layers: the epidermis, dermis, and hypodermis. Any disruption in the integrity of skin leads to the formation of wounds, which are divided into 2 main categories: acute wounds and chronic wounds. Generally, acute wounds heal relatively faster. In contrast to acute wounds, closure of chronic wounds is delayed by 3 months after the initial insult. Treatment of chronic wounds has been one of the most challenging issues in the field of regenerative medicine, promoting scientists to develop various therapeutic strategies for a fast, qualified, and most cost-effective treatment modality. Here, we reviewed more recent approaches, including the development of stem cell therapy, tissue-engineered skin substitutes, and skin equivalents, for the healing of complex wounds.

Comparative analysis of cytokine profiles of glaucomatous tears and aqueous humour reveals potential biomarkers for trabeculectomy complications

Glaucoma is a multifactorial neurodegenerative disease that causes impaired vision and, in advanced cases, blindness. The increasing prevalence of glaucoma due to an ageing population has necessitated the identification of suitable biomarkers for the early detection of the disease. Aqueous humour (AH) has been proposed as a source of biomarkers, but it can only be collected using a minor, yet invasive surgical intervention. Tears, however, are constantly available and can be collected any time via noninvasive methods. In order to examine the utility of tear as a surrogate for aqueous humour in biomarker development, we compared the levels of 27 cytokines and chemokines in paired samples of tear and aqueous humour using a Luminex multiplex immunobead-based technique. Significantly higher levels of cytokines in tear compared to aqueous humour were detected suggesting that tear and aqueous humour are not identical in terms of inflammation response. Furthermore, the levels of IFN-γ, GM-CSF and IL-5 in tear were significantly lower in patients who developed complications after one year, but no statistically significant changes in cytokine levels were observed in aqueous humour. These three molecules may have potential as predictive biomarkers for the appearance of late flap-related complications of trabeculectomy.

Does ocular inflammation play a role in xeroderma pigmentosum with endothelial dysfunction: an immunological study

We report a case of xeroderma pigmentosum (XP) with endothelial dysfunction where the analysis of tears revealed elevated levels of proinflammatory cytokines, even in the absence of active inflammation and neovascularisation of the ocular surface. Although the role of ultraviolet (UV) radiation-induced inflammation in the occurrence of ocular manifestations of XP is known, little is published on the molecular mechanisms and there are no reports quantifying the presence of inflammatory cytokines in the tears of patients with ocular involvement of XP. Tear analysis demonstrated an increase in inflammatory cytokines and chemokines, especially interleukin-8 (2.38 ng/µg), tumour necrosis factor alpha (0.87 ng/µg) and granulocyte monocyte colony stimulating factor (0.44 ng/µg) as compared with the control eye. Effective management of the underlying UV-induced inflammation and promoting DNA repair may play a vital role in managing ocular manifestations and its sequelae in patients of XP.

Genistein inhibits Aβ25-35 -induced SH-SY5Y cell damage by modulating the expression of apoptosis-related proteins and Ca2+ influx through ionotropic glutamate receptors

In this study, we investigated the protective effects of genistein against SH-SY5Y cell damage induced by β-amyloid 25-35 peptide (Aβ_25-35 ) and the underlying mechanisms. Aβ-induced neuronal death, apoptosis, glutamate receptor subunit expression, Ca²⁺ ion concentration, amino acid transmitter concentration, and apoptosis-related factor expression were evaluated to determine the effects of genistein on Aβ-induced neuronal death and apoptosis. The results showed that genistein increased the survival of SH-SY5Y cells and decreased the level of apoptosis induced by Aβ_25-35 . In addition, genistein reversed the Aβ_25-35 -induced changes in amino acid transmitters, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptors, and N-methyl-d-aspartate (NMDA) receptor subunits in SH-SY5Y cells. Aβ_25-35 -induced changes in Ca²⁺ and B-cell lymphoma-2 (Bcl-2) and Bcl-2-associated X (Bax) protein and gene levels in cells were also reversed by genistein. Our data suggest that genistein protects against Aβ_25-35 -induced damage in SH-SY5Y cells, possibly by regulating the expression of apoptosis-related proteins and Ca²⁺ influx through ionotropic glutamate receptors.

Topically administered rhGM-CSF affects PPARβ expression in the stasis zone

Using a rat comb thermal damage model, we investigated the effects of topically administered recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) on peroxisome proliferator-activated receptor PPARβ expression. We created bilateral comb scald models on the backs of fifty Sprague-Dawley rats. The left sides of the backs served as the experimental group and the right sides served as the control group. The experimental group received topically applied rhGM-CSF hydrogel and the control group did not. The survival situations of the stasis zones were compared between the experimental and control groups on the 1st, 3rd, 7th, 14th and 21st post-burn days. Tissues from the surviving stasis zones of both groups were collected at different time-points. Reverse transcriptase-polymerase chain reaction (RT-PCR) and western blotting were used to detect the PPARβ mRNA and protein expression levels. Immunohistochemical methods were applied to detect the localization of PPARβ protein expression. The results showed that, first, the tissue viability numbers for the stasis zones of the experimental group were significantly increased compared with those of the control group. Second, RT-PCR revealed that the PPARβ mRNA expression first increased and then gradually declined in both groups. At all time-points, the expression level in the experimental group was increased compared with that in the control group and the highest expression levels were observed in both groups on the 3rd post-burn day. Third, western blot analysis revealed that the PPARβ protein expression in both groups increased after thermal damage and then gradually decreased. PPARβ protein expression in the experimental group was greater than that in the control group, and the highest expression quantities in both groups were observed on the 3rd post-burn day. In conclusion, rhGM-CSF hydrogel effectively promotes the expression of PPARβ, and the hydrogel had a specific protective effect for the stasis zone.

Stimulatory versus suppressive effects of GM-CSF on tumor progression in multiple cancer types

Granulocyte-macrophage colony-stimulating factor (GM-CSF, also called CSF-2) is best known for its critical role in immune modulation and hematopoiesis. A large body of experimental evidence indicates that GM-CSF, which is frequently upregulated in multiple types of human cancers, effectively marks cancer cells with a ‘danger flag' for the immune system. In this context, most studies have focused on its function as an immunomodulator, namely its ability to stimulate dendritic cell (DC) maturation and monocyte/macrophage activity. However, recent studies have suggested that GM-CSF also promotes immune-independent tumor progression by supporting tumor microenvironments and stimulating tumor growth and metastasis. Although some studies have suggested that GM-CSF has inhibitory effects on tumor growth and metastasis, an even greater number of studies show that GM-CSF exerts stimulatory effects on tumor progression. In this review, we summarize a number of findings to provide the currently available information regarding the anticancer immune response of GM-CSG. We then discuss the potential roles of GM-CSF in the progression of multiple types of cancer to provide insights into some of the complexities of its clinical applications.