Vitamin D3 analogue facilitates epithelial wound healing through promoting epithelial-mesenchymal transition via the Hippo pathway

Plasma vitamin D status and its association with biochemical, clinical and humanistic outcomes in diabetic foot infection patients: a prospective observational study in a tertiary healthcare facility

BACKGROUND

The study aimed to determine the association of vitamin D3 status with biochemical, clinical, and quality of life (QoL) in diabetic foot infection (DFI) patients.

RESEARCH DESIGN AND METHODS

A longitudinal study was conducted in a tertiary care hospital. Baseline biochemical (glycemic, renal, plasma vitamin D3), clinical, and QoL data of the DFI patients were collected. Patients were followed up with over the telephone for four months to assess clinical outcomes (healed/not healed). A subgroup analysis was performed to investigate the effect of vitamin D3 supplementation.

RESULTS

Eighty-nine DFI patients were enrolled, with a median age of 55 years and a male predominance (89.9%). A significant association between vitamin D3 levels and clinical outcome was not observed (p = 0.66). A moderate correlation was observed with the neutrophil-lymphocyte ratio (r = 0.24, p = 0.02). Regarding QoL, emotions (domain) were significantly associated with vitamin D3 levels (p < 0.01). The subgroup analysis showed that vitamin D3 supplements did not affect the clinical outcome.

CONCLUSION

The plasma vitamin D3 levels and vitamin D3 supplements do not significantly affect the biochemical, clinical, and humanistic outcomes, indicating vitamin D3 did not have a positive effect on DFI patients.

Divergent effects of vitamin D3 on human dermal fibroblasts and keratinocytes in wound repair: Implications for therapeutic targeting in tissue remodelling and scarring

BACKGROUND

Vitamin D is known to regulate inflammation and immunity, suggesting it may play a role in wound healing. However, its mechanism of action in key skin cell types-keratinocytes and fibroblasts-involved in wound repair is poorly understood.

OBJECTIVES

This study aimed to elucidate the impact of vitamin D3 and its precursors on keratinocyte and fibroblast behaviour during wound healing using human ex vivo skin explant and primary cell culture models.

METHODS

The rate of closure of incisional wounds made on human ex vivo skin explants treated with the vitamin D3 precursor, cholecalciferol, or the active form 1,25(OH)2D3 was measured over 6 days in culture. Primary cultures of human keratinocytes and dermal fibroblasts were propagated from female facial skin, and changes in gene expression and physiological responses to cholecalciferol or 1,25(OH)2D3 were assessed using various techniques, including scratch wound assays, quantitative reverse transcription polymerase chain reaction, zymography, and immunocytochemistry.

RESULTS

1,25(OH)2D3 significantly increased the early wound closure rate in ex vivo human skin explants, while cholecalciferol had no effect. 1,25(OH)2D3 accelerated keratinocyte migration but inhibited fibroblast migration and their transition into pro-fibrotic myofibroblasts, reducing extracellular matrix remodelling. Using small interfering RNA, it was established that responses were mediated by vitamin D receptor signalling.

CONCLUSIONS

This study highlighted the divergent effects of vitamin D on keratinocyte and fibroblast wound responses, i.e., promoting re-epithelialisation, while potentially suppressing aberrant fibrosis. Optimising vitamin D status may facilitate wound repair while minimising scarring, which has implications for treating non-healing wounds and excessive scarring disorders.

Effects of vitamin D status on cutaneous wound healing through modulation of EMT and ECM

To investigate the effects of vitamin D status on cutaneous wound healing, C57BL/6J mice were fed diets with different vitamin D levels or injected intraperitoneally with 1α,25(OH)2D3. Dorsal skin wounds were created and wound edge tissues were collected on days 4, 7, 11, and 14 postwounding. The proliferation and migration of HaCaT cells treated with shVDR or 1α,25(OH)2D3 were assessed. Vitamin D deficiency (VDD) decreased wound closure and might delay inflammatory response, shown by slower inflammatory cell infiltration, decreased IL6 and TNF expression in early phase followed by an increase later. VDD might postpone epithelial-mesenchymal transition (EMT), initially characterized by higher epithelial markers and lower mesenchymal markers, followed by opposite appearance later. Dietary vitamin D supplementation and 1α,25(OH)2D3 intervention tended to accelerate EMT. Regarding extracellular matrix (ECM), VDD appeared to reduce collagen deposition on day 4 and downregulated fibronectin, COL3A1, and MMP9 expression early, followed by an increase later, together with an initial increase and subsequent decrease in Timp1 mRNA expression. Dietary vitamin D intervention promoted fibronectin and MMP9 expression on day 4 and then downregulated their expression on day 14. TGFb1/SMAD2/3 signaling seemed to be downregulated by VDD and upregulated by 1α,25(OH)2D3. In vitro, partial inhibition of VDR by shVDR tended to inhibit HaCaT cell proliferation and migration, EMT, and TGFb1/SMAD2/3 signaling, whereas 1α,25(OH)2D3 appeared to generate opposite effects. In conclusion, VDD hindered cutaneous wound healing, potentially due to impaired inflammatory response, delayed EMT, decreased ECM, and inhibited TGFb1/SMAD2/3 pathway. Vitamin D and 1α,25(OH)2D3 tended to enhance EMT and ECM.

Telmisartan ameliorates nephropathy and restores the hippo pathway in rats with metabolic syndrome

The main objective of this study was to determine if the telmisartan-ameliorative effects of metabolic syndrome (MetS)-evoked nephropathy are attributed to the Hippo pathway. A secondary objective was to investigate the potential of vitamin D3 to enhance telmisartan-favourable effects. A diet composed of 24% fat and 3% salt, along with drinking water containing 10% fructose, was administered for 12 weeks to induce MetS. MetS-rats were given telmisartan (5 mg/kg/day), vitamin D3 (10 μg/kg/day) or both by gavage, starting in the sixth week of experimental diet administration. Assessments performed at closure included renal function, histological examination, catalase, malondialdehyde (MDA), nuclear factor kappa-B (NF-κB), interleukin-6 (IL-6), peroxisome proliferator-activated receptor-γ (PPAR-γ), phosphatase and tensin homolog (PTEN), and transforming growth factor-β (TGF-β). Matrix metalloproteinase-9 (MMP-9) immunostaining was conducted. The expression of the Hippo pathway components, as well as that of angiotensin II type 1 and type 2 (AT1 and AT2), receptors was evaluated. Telmisartan attenuated MetS-evoked nephropathy, as demonstrated by improvement of renal function and histological features, enhancement of catalase, reduction of MDA, inflammation (NF-κB, IL-6), and renal fibrosis (increased PPAR-γ and PTEN and reduced MMP-9 and TGF-β). Telmisartan downregulated AT1-receptor, upregulated AT2-receptor and restored the Hippo pathway. Vitamin D3 replicated most of the telmisartan-elicited effects and enhanced the antifibrotic actions of telmisartan. The alleviative effects of telmisartan on MetS-evoked nephropathy may be related to the restoration of the Hippo pathway. The combination of vitamin D3 and telmisartan exerted more favourable effects on metabolic and nephropathic biomarkers compared with either one administered alone.

1,25(OH)2D3 improves diabetic wound healing by modulating inflammation and promoting angiogenesis

Vitamin D was found to regulate inflammatory response and angiogenesis, which were often impaired in diabetic wound healing. This study aimed to investigate the effects of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] on diabetic wound healing both in vivo and in vitro. Diabetes was induced by high-fat diet combined with streptozotocin. After four weeks of establishing diabetic mouse model, full-thickness excisional wounds were created on their dorsal skin. Then 1,25(OH)2D3 was administered via intraperitoneal injection for 14 consecutive days. Human umbilical vein endothelial cells (HUVECs) were cultured with normal glucose, high glucose, high glucose plus 1,25(OH)2D3. Cell proliferation, migration, tube formation, and expression levels of relevant pathway components were measured. Intervention with 1,25(OH)2D3 significantly increased wound closure rates of diabetic mice. During the inflammatory phase, 1,25(OH)2D3 alleviated excessive inflammation and promoted the transition of macrophages from M1 to M2 phenotype. Regarding vascular endothelial function, 1,25(OH)2D3 significantly up-regulated eNOS protein expression and inhibited Vcam-1 mRNA expression in diabetic mice (P < 0.05). As for angiogenesis, 1,25(OH)2D3 markedly increased CD31-positive area, the protein and mRNA expression of VEGF, VEGFR2, PDGF, and PDGFRβ, as well as the mRNA expression of Bfgf and Egfr (P < 0.05). In vitro, 1,25(OH)2D3 restored impaired cell proliferation, migration, and tube formation induced by high-glucose, and up-regulated expression of angiogenesis-related factors. These protective effects might be mediated through PI3K/AKT/HIF-1α pathway. These findings suggested that 1,25(OH)2D3 accelerated diabetic wound healing by modulating inflammation, restoring vascular endothelial dysfunction, and promoting angiogenesis.

Knockdown of LRCH4 Remodels Tumor Microenvironment Through Inhibiting YAP and TGF-β/Smad Signaling Pathway in Colorectal Cancer

BACKGROUND

Colorectal cancer is one of the most common gastrointestinal malignancies worldwide. LRCH4 is the top 1 gene associated with an unfavorable prognosis in colorectal cancer.

METHODS

Here, we reported that the knockdown of LRCH4 inhibited the proliferation, migration and invasion in HT29 cells.

RESULTS

The activity of Yes-Associated Protein (YAP), a transcription factor in the Hppo-YAP signaling pathway, was significantly inhibited by LRCH4-siRNA. LRCH4 knockdown also reversed the EMT and regulated the expression of extracellular matrix (ECM) protein, Fibronectin and Collagen IV in HT29 cells. In addition, the TGF-β/Smad signaling pathway, as the downstream pathway of Yap, was also inhibited by LRCH4 knockdown.

CONCLUSION

Knockdown of LRCH4 involved in the regulation of ECM and EMT and inhibited YAP and the TGF-β/Smad signaling pathway in colorectal cancer cells. Our study provided a mechanism of LRCH4 on colorectal cancer cells, and a new potential target for clinical tumor treatment.

Vitamin D and wound healing: Assessing skin barrier function and implications for chloasma treatment

Chloasma, which is distinguished by irregularities in the pigmentation of skin, poses substantial challenge in the field of dermatology. The regulatory influence of vitamin D on the functions of skin cells implies that it may have the capacity to effectively treat chloasma and promote wound healing. To assess the efficacy of vitamin D in chloasma treatment and its impact on the function of skin barrier during the process of wound healing. The research spanned from April 2022 to September 2023, in Shanghai, China, examined 480 individuals who had been diagnosed with chloasma. A double-blind, placebo-controlled clinical trial was utilized to evaluate effectiveness of topical vitamin D3 in treatment of chloasma. Concurrently, randomized control trial investigated the effects of ingested vitamin D3 supplements on the process of wound healing. Transepidermal water loss (TEWL), chloasma severity score changes, wound size reduction and skin hydration levels were critical performance indicators. Statistically, the severity scores of chloasma decreased significantly in the vitamin D treatment group at 3 and 6 months compared with the placebo (p < 0.05). The Vitamin D group exhibited superior wound healing outcomes, including more substantial reduction in lesion size and enhanced skin barrier function, as evidenced by increased skin hydration and decreased TEWL (p < 0.05). Vitamin D substantially mitigated the severity of chloasma and has beneficial effect on wound healing and integrity of the skin barrier. Based on the results obtained, vitamin D exhibited promise as a therapeutic intervention in the field of dermatology, specifically in treatment of chloasma and promotion of wound recovery.

Lactobacillus johnsonii LJO02 (DSM 33828) Cell-Free Supernatant and Vitamin D Improve Wound Healing and Reduce Interleukin-6 Production in Staphylococcus aureus-Infected Human Keratinocytes

Methicillin-resistant biofilm-forming Staphylococcus spp. are found in about 25% of the overall cases of chronic wounds, which can undergo malignant degeneration and be associated with skin cancer. Although antimicrobial agents are clinically used to counteract pathogens and promote wound healing, they are increasingly ineffective against multi-drug resistant bacteria. Moreover, they can induce dysbiosis, which favors opportunistic pathogen infections and alters immune responses. Consequently, research on pathogen containment strategies is crucial. We aimed to evaluate the potential beneficial effect of Lactobacillus johnsonii LJO02 cell-free supernatant (CFS) and vitamin D, as single treatments or in combination, on cell viability, wound healing, and the pro-inflammatory interleukin-6 (IL-6) production of a Staphylococcus aureus-infected human immortalized keratinocyte cell line (HaCaT) in vitro model. The analysis showed that LJO02 CFS 20% v/v ratio and 100 nM vitamin D promoted infected cell viability and wound healing and significantly reduced IL-6 production. However, their effect was not synergic, since no significant difference between the single and combined treatments was observed. LJO02 CFS topic application and vitamin D supplementation could provide a valuable strategy for attenuating S. aureus-induced pathogenesis, promoting wound healing and opening new therapeutic strategies supporting the conventional approaches.

Human Parathyroid Hormone Analog (3-34/29-34) promotes wound re-epithelialization through inducing keratinocyte migration and epithelial-mesenchymal transition via PTHR1-PI3K/AKT activation

BACKGROUND

Re-epithelialization is important in the process of wound healing. Various methods have been identified to expedite the process, but their clinical application remains limited. While parathyroid hormone (PTH) has shown promising results in wound healing due to its role in promoting collagen deposition and cell migration, application is limited by its potentially inhibitive effects when being continuously and locally administrated. Herein, we developed a novel PTH analog, Human parathyroid hormone (hPTH) (3-34/29-34) (henceforth MY-1), by partially replacing and repeating the amino acid sequences of hPTH (1-34), and evaluated its effect on skin wound re-epithelialization.

METHODS

CCK-8, colony formation unit assay, and Ki67 immunofluorescent staining were performed to evaluate the effect of MY-1 on HaCaT cell proliferation. Then, wound scratch assay, Transwell assay and lamellipodia staining were carried out to evaluate the effect of MY-1 on cell migration. Moreover, the epithelial-mesenchymal transition (EMT) markers were measured using qPCR and western blot analysis. For in-vivo drug delivery, gelatin methacryloyl (GelMA) hydrogel was employed to load the MY-1, with the physicochemical characteristics evaluated prior to its application in wound models. Then, MY-1's role in wound healing was determined via acute skin wound models. Finally, the mechanism that MY-1 activated was also detected on HaCaT cells and in-vivo wound models.

RESULTS

In-vitro, MY-1 accelerated the migration and EMT of HaCaT cells, while having little effect on cell proliferation. GelMA and MY-1-incorporated GelMA hydrogels showed similar physicochemical characteristics and were used in the in-vivo studies, where the results revealed that MY-1 led to a stronger re-epithelialization by inducing basal keratinocyte migration and EMT. Further studies on in-vivo wound models and in-vitro HaCaT cells revealed that MY-1 regulated cell migration and EMT through activating PI3K/AKT signaling. The parathyroid hormone type 1 receptor (PTHR1), the main receptor of PTH, was found to be the upstream of PI3K/AKT signaling, through interfering PTHR1 expression with a small interference RNA following detection of the PI3K/AKT activation.

CONCLUSION

Collectively, our study demonstrated that MY-1 accelerates skin wound re-epithelialization by inducing keratinocyte migration and EMT via PTHR1-PI3K/AKT axis activation. Video Abstract.

Recent advances in the role of Yes-associated protein in dermatosis

BACKGROUND

Dermatosis is a general term for diseases of the skin and skin appendages including scleroderma, psoriasis, bullous disease, atopic dermatitis, basal cell carcinoma, squamous cell carcinoma, and melanoma. These diseases affect millions of individuals globally and are a serious public health concern. However, the pathogenesis of skin diseases is not fully understood, and treatments are not optimal. Yes-associated protein (YAP) is a transcriptional coactivator that plays a role in the regulation of gene transcription and signal transduction.

AIMS

To study the role of Yes-associated protein in skin diseases.

MATERIALS AND METHODS

The present review summarizes recent advances in our understanding of the role of YAP in skin diseases, current treatments that target YAP, and potential avenues for novel therapies.

RESULTS

Abnormal YAP expression has been implicated in occurrence and development of dermatosis. YAP regulates the cell homeostasis, proliferation, differentiation, apoptosis, angiopoiesis, and epithelial-to-mesenchymal transition, among other processes. As well as, it serves as a potential target in many biological processes for treating dermatosis.

CONCLUSIONS

The effects of YAP on the skin are complex and require multidimensional investigational approaches. YAP functions as an oncoprotein that can promote the occurrence and development of cancer, but there is currently limited information on the therapeutic potential of YAP inhibition for cancer treatment. Additional studies are also needed to clarify the role of YAP in the development and maturation of dermal fibroblasts; skin barrier function, homeostasis, aging, and melanin production; and dermatosis.

Sodium thiosulfate inhibits epithelial-mesenchymal transition in melanoma via regulating the Wnt/β-catenin signaling pathway

BACKGROUND

Melanoma is the most common form of skin cancer. Given its high metastasis and high recurrence, its therapies are constantly updated.

OBJECTIVE

The study aims to prove the efficacy of sodium thiosulfate (STS), an antidote to cyanide or nitroprusside poisoning, in melanoma treatment.

METHODS

We tested the effect of STS by culturing melanoma cells (B16 and A375) in vitro and establishing melanoma mouse models in vivo. The proliferation and viability of melanoma cells were measured by the CCK-8 test, cell cycle assay, apoptosis analysis, wound healing assay, and transwell migration assay. The expression of apoptosis-related molecules, epithelial-mesenchymal transition (EMT)-associated molecules, and the Wnt/β-catenin signaling pathway-related molecules were determined by Western blotting and immunofluorescence.

RESULTS

The high metastasis of melanoma is considered to be linked to the EMT process. The scratch assay using B16 and A375 cells also showed that STS could inhibit the EMT process of melanoma. We demonstrated that STS inhibited the proliferation, viability, and EMT process of melanoma by releasing H₂S. STS-mediated weakening of cell migration was related to the inhibition of the Wnt/β-catenin signaling pathway. Mechanistically, we defined that STS inhibited the EMT process via the Wnt/β-catenin signaling pathway.

CONCLUSIONS

These results suggest that the negative effect of STS on melanoma development is mediated by the reduction of EMT via the regulation of the Wnt/β-catenin signaling pathway, which provides a new clue to treating melanoma.

FGF4 Promotes Skin Wound Repair through p38 MAPK and GSK3β-Mediated Stabilization of Slug

Cutaneous wound healing is an orderly and intricate process that restores the barrier function and integrity of injured skin. Re-epithelialization, which involves the proliferation and migration of keratinocytes to cover the denuded surface, is essential for successful wound closure. There are many members of the FGF family, of which the paracrine-acting FGF1 and FGF7 subfamily members have been identified as positive regulators of wound repair. However, the role and underlying mechanisms of some other paracrine FGFs in wound repair still remain obscure. In this report, we found that paracrine FGF4 localized predominantly to the epidermal keratinocytes and was markedly upregulated at the wound edges in response to re-epithelialization in human and mouse wound models. Blockade of FGF4 resulted in delayed re-epithelialization of human ex vivo skin wounds, whereas recombinant FGF4 treatment promoted re-epithelialization and wound repair. Mechanistically, recombinant FGF4 promotes p38 MAPK‒GSK3β‒mediated stabilization of Slug by reducing its ubiquitination, which triggers epithelial-to-mesenchymal transition and promotes the migration and proliferation of keratinocytes and thus wound re-epithelialization. Our findings uncover FGF4 as an important regulator of wound healing, highlighting a promising therapeutic avenue for skin injury.

The Hippo signalling pathway and its implications in human health and diseases

As an evolutionarily conserved signalling network, the Hippo pathway plays a crucial role in the regulation of numerous biological processes. Thus, substantial efforts have been made to understand the upstream signals that influence the activity of the Hippo pathway, as well as its physiological functions, such as cell proliferation and differentiation, organ growth, embryogenesis, and tissue regeneration/wound healing. However, dysregulation of the Hippo pathway can cause a variety of diseases, including cancer, eye diseases, cardiac diseases, pulmonary diseases, renal diseases, hepatic diseases, and immune dysfunction. Therefore, therapeutic strategies that target dysregulated Hippo components might be promising approaches for the treatment of a wide spectrum of diseases. Here, we review the key components and upstream signals of the Hippo pathway, as well as the critical physiological functions controlled by the Hippo pathway. Additionally, diseases associated with alterations in the Hippo pathway and potential therapies targeting Hippo components will be discussed.

Harnessing Multifaceted Next-Generation Technologies for Improved Skin Wound Healing

Dysregulation of sequential and synchronized events of skin regeneration often results in the impairment of chronic wounds. Conventional wound dressings fail to trigger the normal healing mechanism owing to the pathophysiological conditions. Tissue engineering approaches that deal with the fabrication of dressings using various biomaterials, growth factors, and stem cells have shown accelerated healing outcomes. However, most of these technologies are associated with difficulties in scalability and cost-effectiveness of the products. In this review, we survey the latest developments in wound healing strategies that have recently emerged through the multidisciplinary approaches of bioengineering, nanotechnology, 3D bioprinting, and similar cutting-edge technologies to overcome the limitations of conventional therapies. We also focus on the potential of wearable technology that supports complete monitoring of the changes occurring in the wound microenvironment. In addition, we review the role of advanced devices that can precisely enable the delivery of nanotherapeutics, oligonucleotides, and external stimuli in a controlled manner. These technological advancements offer the opportunity to actively influence the regeneration process to benefit the treatment regime further. Finally, the clinical relevance, trajectory, and prospects of this field have been discussed in brief that highlights their potential in providing a beneficial wound care solution at an affordable cost.

Targeting the ILK/YAP axis by LFG-500 blocks epithelial-mesenchymal transition and metastasis

Metastasis is the main cause of mortality in patients with cancer. Epithelial-mesenchymal transition (EMT), a crucial process in cancer metastasis, is an established target for antimetastatic drug development. LFG-500, a novel synthetic flavonoid, has been revealed as a potential antitumor agent owing to its various activities, including modulation of EMT in the inflammatory microenvironment. Here, using a transforming growth factor beta (TGF-β)-induced EMT models, we found that LFG-500 inhibited EMT-associated migration and invasion in human breast cancer, MCF-7, and lung adenocarcinoma, A549, cell lines, consistent with the observed downregulation of YAP activity. Further studies demonstrated that LGF-500-induced suppression of YAP activation was mediated by integrin-linked kinase (ILK), suggesting that the ILK/YAP axis might be feasible target for anti-EMT and antimetastatic treatments, which was verified by a correlation analysis with clinical data and tumor specimens. Hence, our data support the use of LGF-500 as an antimetastatic drug in cancer therapy and provide evidence that the ILK/YAP axis is a feasible biomarker of cancer progression and a promising target for repression of EMT and metastasis in cancer therapy.