EGFL7-overexpressing epidermal stem cells promotes fibroblast proliferation and migration via mediating cell adhesion and strengthening cytoskeleton

Standardized GMP-Compliant Scalable 3D-Bioprocessing of Epidermal Stem Cells for Diabetic Foot Ulcers

Diabetic foot ulcers (DFUs) pose a significant threat to the health and well-being of individuals with diabetes, often leading to lower limb amputations. Fortunately, epidermal stem cell therapy offers hope for improving the treatment of DFUs. By leveraging 3D culture techniques, the scalability of stem cell manufacturing can be greatly enhanced. In particular, using bioactive materials and scaffolds can promote the healing potential of cells, enhance their proliferation, and facilitate their survival. Furthermore, 3D tissue-mimicking cultures can accurately replicate the complex interactions between cells and extracellular matrix, thereby ensuring that the stem cells are primed for therapeutic application. To ensure the safety and quality of these stem cells, it is essential to adhere to good manufacturing practice (GMP) principles during cultivation. This chapter provides a comprehensive overview of the step-by-step process for GMP-based 3D epidermal stem cell cultivation, thus laying the groundwork for developing reliable regenerative medicine therapies.

Hepatocellular carcinoma cells remodel the pro-metastatic tumour microenvironment through recruitment and activation of fibroblasts via paracrine Egfl7 signaling

BACKGROUND

The tumour microenvironment consists of a complex and dynamic milieu of cancer cells, including tumour-associated stromal cells (leukocytes, fibroblasts, vascular cells, etc.) and their extracellular products. During invasion and metastasis, cancer cells actively remodel the tumour microenvironment and alterations of microenvironment, particularly cancer-associated fibroblasts (CAFs), can promote tumour progression. However, the underlying mechanisms of the CAF formation and their metastasis-promoting functions remain unclear.

METHODS

Primary liver fibroblasts and CAFs were isolated and characterized. CAFs in clinical samples were identified by immunohistochemical staining and the clinical significance of CAFs was also analysed in two independent cohorts. A transwell coculture system was used to confirm the role of HCC cells in CAF recruitment and activation. qRT-PCR, western blotting and ELISA were used to screen paracrine cytokines. The role and mechanism of Egfl7 in CAFs were explored via an in vitro coculture system and an in vivo mouse orthotopic transplantation model.

RESULTS

We showed that CAFs in hepatocellular carcinoma (HCC) are characterized by the expression of α-SMA and that HCC cells can recruit liver fibroblasts (LFs) and activate them to promote their transformation into CAFs. High α-SMA expression, indicating high CAF infiltration, was correlated with malignant characteristics. It was also an independent risk factor for HCC survival and could predict a poor prognosis in HCC patients. Then, we demonstrated that EGF-like domain multiple 7 (Egfl7) was preferentially secreted by HCC cells, and exhibited high potential to recruit and activate LFs into the CAF phenotype. The ability of Egfl7 to modulate LFs relies upon increased phosphorylation of FAK and AKT via the receptor α_νβ₃ integrin. Strikingly, CAFs activated by paracrine Egfl7 could further remodel the tumour microenvironment by depositing fibrils and collagen and in turn facilitate HCC cell proliferation, invasion and metastasis.

CONCLUSION

Our data highlighted a novel role of Egfl7 in remodelling the tumour microenvironment: it recruits LFs and activates them to promote their transformation into CAFs via the α_νβ₃ integrin signaling pathway, which further promotes HCC progression and contributes to poor clinical outcomes in HCC patients. Video Abstract.

EGFL7 affects the migration of epidermal stem cells in refractory diabetic wounds by regulating Notch signaling pathway

Aim: This study aimed to explore the role of EGFL7 in the healing process of refractory diabetic wounds. Methods: Epidermal stem cells (ESCs) were isolated from healthy mice and diabetic mice, identified by immunofluorescence, transfected with EGFL7 overexpression and silencing lentiviral vectors, and treated with Notch pathway inhibitor (DAPT). Results: SiEGFL7 significantly inhibited the proliferation, invasion and migration of ESCs of healthy mice. DAPT prominently inhibited the expressions of Notch1, Notch2, Hes1 and Jag1 in ESCs of healthy mice induced by overexpressed EGFL7. Overexpressed EGFL7 promoted wound healing in diabetic mice with refractory wounds. Conclusion: EGFL7 affects the proliferation and migration of ESCs in refractory diabetic wounds by regulating the Notch signaling pathway.

Copper-containing titanium alloys promote angiogenesis in irradiated bone through releasing copper ions and regulating immune microenvironment

Poor vascularization was demonstrated as a factor inhibiting bone regeneration in patients receiving radiotherapy. Various copper-containing materials have been reported to increase angiogenesis, therefore might improve bone formation. In this study, a Ti6Al4V-1.5Cu alloy was prepared using selective laser melting (SLM) technology. The immunomodulatory and pro-angiogenic effects of the Ti6Al4V-1.5Cu alloys were examined. In vitro, Ti6Al4V-1.5Cu stimulated vascular formation by restraining inflammatory factors and provoking angiogenic factors in non-irradiated and irradiated macrophages. In vivo, the angiogenic effects of the Ti6Al4V-1.5Cu alloy were confirmed using an irradiated rat femur defect model. Moreover, we found that the biological effects of the Ti6Al4V-1.5Cu alloy were partially due to the release of copper ions and associated with PI3K-Akt signaling pathway. In conclusion, this study indicated the potential of the Ti6Al4V-1.5Cu alloy to promote angiogenesis by releasing copper ions and inhibiting inflammation in normal and irradiated tissues.

Clinical Translational Potentials of Stem Cell-Derived Extracellular Vesicles in Type 1 Diabetes

Type 1 diabetes (T1D) is an organ-specific disease characterized by the deficiency of insulin caused by the autoimmune destruction of pancreatic islet β cells. Stem cell-based therapies play essential roles in immunomodulation and tissue regeneration, both of which hold great promise for treating many autoimmune dysfunctions. However, their clinical translational potential has been limited by ethical issues and cell transplant rejections. Exosomes are small extracellular vesicles (EVs) released by almost all types of cells, performing a variety of cell functions through the delivery of their molecular contents such as proteins, DNAs, and RNAs. Increasing evidence suggests that stem cell-derived EVs exhibit similar functions as their parent cells, which may represent novel therapeutic agents for the treatment of autoimmune diseases including T1D. In this review, we summarize the current research progresses of stem cell-derived EVs for the treatment of T1D.

Comparative Analysis of KGF-2 and bFGF in Prevention of Excessive Wound Healing and Scar Formation in a Corneal Alkali Burn Model

PURPOSE

Basic fibroblast growth factor (bFGF) is an effective drug for corneal injury. However, the explicit role of bFGF in corneal scar formation still remains unclear. Keratinocyte growth factor-2 (KGF-2) is associated with the treatment of wound healing. We aimed to compare the efficacy of bFGF and KGF-2 in prevention of excessive wound healing and consequent scar formation in a rat alkali burn model, which provides important clues on the significance of KGF-2 to be developed as a new drug for such injuries.

METHODS

The epithelial defect area was evaluated using fluorescein sodium at a concentration of 0.5%. The therapeutic effect of KGF-2 and bFGF on proliferation of rabbit corneal fibroblasts (RCFs) was evaluated by methylthiazoletetrazolium. RCF migration assays were performed with a modified scratch method. Activation of mitogen-activated protein kinase (MAPK) was evaluated by Western blot with specific antibodies.

RESULTS

All corneal wounds treated with KGF-2 were found closed within 7 days; however, the wounds treated with bFGF or phosphate buffer saline (PBS) required 14 days to close. RCFs treated with KGF-2 or bFGF showed similar dose-dependent proliferation. The KGF-2 group significantly promoted cell migration compared with the bFGF group. The KGF-2 group showed less expression of α-smooth muscle actin (SMA) and numbers of myofibroblasts compared with the bFGF group. Our findings suggested identification of cascade reaction of extracellular regulated protein kinases (ERK)1/2 and p38 signals in KGF-2- and bFGF-induced proliferation and migration of RCFs. In addition, KGF-2 showed stronger effects during ERK1/2 and p38 phosphorylation in methylthiazoletetrazolium proliferation assay and scratch migration assay.

CONCLUSIONS

KGF-2 exhibited better effects than bFGF in reepithelialization, acceleration of migration, and reduction of scar formation, which has potential to become a new drug to cure corneal injury.

Gene microarray integrated with iTRAQ-based proteomics for the discovery of NLRP3 in LPS-induced inflammatory response of bovine mammary epithelial cells

Mastitis, a major infectious disease in dairy cows, is characterized by an inflammatory response to pathogens such as Escherichia coli and Staphylococcus aureus. To better understand the immune and inflammatory response of the mammary gland, we stimulated bovine mammary gland epithelial cells (BMECs) with E. coli-derived lipopolysaccharide (LPS). Using transcriptomic and proteomic analyses, we identified 1019 differentially expressed genes (DEGs, fold change ≥2 and P-value < 0.05) and 340 differentially expressed proteins (DEPs, fold change ≥1.3 and P-value < 0.05), of which 536 genes and 162 proteins were upregulated and 483 genes and 178 proteins were downregulated following exposure to LPS. These differentially expressed genes were associated with 172 biological processes; 15 Gene Ontology terms associated with response to stimulus, 4 associated with immune processes, and 3 associated with inflammatory processes. The DEPs were associated with 51 biological processes; 2 Gene Ontology terms associated with response to stimulus, 1 associated with immune processes, and 2 associated with inflammatory processes. Meanwhile, several pathways involved in mammary inflammation, such as Toll-like receptor, NF-κB, and NOD-like receptor signaling pathways were also represented. NLRP3 depletion significantly inhibited the expression of IL-1β and PTGS2 by blocking caspase-1 activity in LPS-induced BMECs. These results suggest that NLR signaling pathways works in coordination with TLR4/NF-κB signaling pathways via NLRP3-inflammasome activation and pro-inflammatory cytokine secretion in LPS-induced mastitis. The study highlights the function of NLRP3 in an inflammatory microenvironment, making NLRP3 a promising therapeutic target in Escherichia coli mastitis.

Advanced Glycation End Products (AGEs) Induce Apoptosis of Fibroblasts by Activation of NLRP3 Inflammasome via Reactive Oxygen Species (ROS) Signaling Pathway

Background

Type 2 diabetes impairs the healing process and induces apoptosis of fibroblasts, which are thought to be involved in this process. We investigated the possible mechanisms involved in AGEs-induced apoptosis of human dermal fibroblasts.

Material/Methods

We examined the expression of apoptosis-related proteins in fibroblasts isolated from human diabetic wounds. Human dermal fibroblasts exposed to AGEs were used to study the links among apoptosis, ROS, and NLRP3 inflammasome activation. Signaling mechanisms were evaluated by preincubating the cells with appropriate inhibitors. Cleaved caspase-8, cleaved caspase-3, BAX, Bcl-2, and NLRP3 inflammasome expression were measured by Western blot analysis. ROS generation, cell viability, and cell apoptosis were assessed.

Results

We observed a higher level of cleaved caspase-8 and cleaved caspase-3 expression in fibroblasts isolated from human diabetic wounds compared with controls. AGEs decreased the proliferation of cells in a concentration-dependent and time-dependent manner. The exposure of fibroblasts to AGEs significantly increased the number of cells in early and late apoptosis stages. AGES-induced human dermal fibroblasts showed high expressions of cleaved caspase3, cleaved caspase8, and Bax. Treatment with AGEs induced the expression of NLRP3, caspase-1, and ASC. AGES-induced apoptosis was blocked by BAY 11–7082, an inhibitor of the NLRP3 inflammasome. AGEs increased the production of ROS in fibroblasts, and its apoptogenic effect was blocked by NAC.

Conclusions

AGEs cause apoptosis of fibroblasts by inducing the generation of ROS and activating the NLRP3 inflammasome. In vivo experiments are needed to confirm these results.

Epidermal stem cells in wound healing and their clinical applications

The skin has important barrier, sensory, and immune functions, contributing to the health and integrity of the organism. Extensive skin injuries that threaten the entire organism require immediate and effective treatment. Wound healing is a natural response, but in severe conditions, such as burns and diabetes, this process is insufficient to achieve effective treatment. Epidermal stem cells (EPSCs) are a multipotent cell type and are committed to the formation and differentiation of the functional epidermis. As the contributions of EPSCs in wound healing and tissue regeneration have been increasingly attracting the attention of researchers, a rising number of therapies based on EPSCs are currently under development. In this paper, we review the characteristics of EPSCs and the mechanisms underlying their functions during wound healing. Applications of EPSCs are also discussed to determine the potential and feasibility of using EPSCs clinically in wound healing.

miR-29b-3p promotes progression of MDA-MB-231 triple-negative breast cancer cells through downregulating TRAF3

BACKGROUND

Breast cancer is the second common malignant cancer among females worldwide. Accumulating studies have indicated that deregulation of miRNA expression in breast cancer will contribute to tumorigenesis and form different cancer subtypes. However, the reported studies on miR-29b-3p-regulated breast cancer are limited so far. Herein, we investigated the role and mechanism of miR-29b-3p in the triple negative breast cancer cell line MDA-MB-231.

METHODS

The relative miR-29b-3p expression in different breast cancer cell lines were determined by qRT-PCR. CCK8 and colony formation assay were used to determine the influence of miR-29b-3p on cell proliferation. Migration assay and invasion assay were performed for cell migration and invasion respectively. To study the cell integrity immunofluorescence was performed. TUNEL assay, flow cytometry assay, hoechst staining and western blot were conducted to determine the influence of miR-29b-3p inhibitor on cell apoptosis. TRAF3 was found to be the target gene of miR-29b-3p using bioinformatics predictions. Dual-luciferase assay was performed to determine the relative luciferase activity in NC, miR-29b-3p mimic, miR-29b-3p inhibitor with TRAF3 3'-UTR wt or TRAF3 3'-UTR mt reporter plasmids. The proteins expression of NF-κB signaling pathway in MDA-MB-231 after transfection with NC, miR-29b-3p mimic, miR-29b-3p inhibitor were determined by western blot.

RESULTS

The miR-29b-3p expression was significantly increased in MDA-MB-231 compare with MCF-10A. miR-29b-3p inhibitor reduced the cell viability of MDA-MB-231 and inhibited cell migration and invasion. Cell cytoskeleton integrity destroyed after miR-29b-3p inhibitor treatment. Furthermore, we identified the mechanism and found miR-29b-3p targets the TRAF3 and activates NF-κB signaling pathway.

CONCLUSIONS

From the above studies, our results indicated that miR-29b-3p acts as a promoter for the development of MDA-MB-231.

Genetic association and functional characterization of MCPH1 gene variation in bipolar disorder and schizophrenia

A rare microcephalin 1 gene (MCPH1) variant rs61749465A>G (p.Asp61Gly) with prior evidence for association with schizophrenia (p = 3.78 × 10-7 ) was tested for association in 2,300 bipolar disorder (BPD) participants, 1,930 SCZ participants and 1,820 normal comparison subjects. We report evidence for association of rs61749465A>G with BPD (p = 0.0009). rs61749465 is located in the N-terminal of the BRCT1 domain of MCPH1. Bioinformatic analysis predicted the Asp61Gly substitution to be damaging to MCPH1 function. A second MCPH1 BRCT1 domain variant (rs199422124C>G; p.Thr27Arg), reported to cause autosomal recessive microcephaly, was not detected in the participants tested here. We sought to characterize the functional effects of these variants on MCPH1 function. Cell count assays indicated that rs199422124 allele G had a greater impact on cell survival compared to the G allele of rs61749465. Gene expression analysis combined with gene network and pathway analysis indicated that rs61749465 allele G may impact protein translation and cell cycle control. The evidence for association between rs61749465A>G and psychosis in both BPD and SCZ warrants further replication. Likewise, the data from the functional analyses point to molecular mechanisms that may underlie the proposed MCPH1 mediated risk of psychosis and pathogenesis in autosomal recessive microcephaly require additional experimental validation.

A positive feed-forward loop between LncRNA-URRCC and EGFL7/P-AKT/FOXO3 signaling promotes proliferation and metastasis of clear cell renal cell carcinoma

Background

The aberrant expression of long noncoding RNAs (lncRNAs) has recently emerged as key molecules in human cancers; however, whether lncRNAs are implicated in the progression of clear cell renal cell carcinoma (ccRCC) remains unclear.

Methods

Candidate lncRNAs were selected using microarray analysis and quantitative real-time PCR (qRT-PCR) was performed to detect lncRNAs expression in human ccRCC tissues. Overexpression and knocking down experiments in vivo and in vitro were performed to uncover the biological roles of lncRNA-URRCC on ccRCC cell proliferation and invasion. Microarray, chromatin immunoprecipitation, Luciferase reporter assay and western blot were constructed to investigate the molecular mechanisms underlying the functions of lncRNA-URRCC.

Results

The microarray analysis and qRT-PCR identified a new lncRNA, URRCC, whose expression is upregulated in RCC samples and associated with poor prognosis, leading to promote ccRCC cell proliferation and invasion. Mechanistically, URRCC enhances the expression of EGFL7 via mediating histone H3 acetylation of EGFL7 promoter, activation of P-AKT signaling, and suppressing P-AKT downstream gene, FOXO3. In return, FOXO3 could inhibit the transcription of URRCC via binding to the special region on the promoter of URRCC.

Conclusions

Our data suggests that targeting this newly identified feed-back loop between LncRNA-URRCC and EGFL7/P-AKT/FOXO3 signaling may enhance the efficacy of existing therapy and potentially imparts a new avenue to develop more potent therapeutic approaches to suppress RCC progression.

Electronic supplementary material

The online version of this article (10.1186/s12943-019-0998-y) contains supplementary material, which is available to authorized users.

Epidermal Growth Factor Like-domain 7 and miR-126 are abnormally expressed in diffuse Systemic Sclerosis fibroblasts

Systemic sclerosis (SSc) is characterized by microangiopathy with impaired reparative angiogenesis and fibrosis. Epidermal Growth Factor Like-domain 7 (EGFL7), firstly described in endothelial cells plays a pivotal role in angiogenesis. Fibroblasts (FBs) are involved in vascular remodeling, under physiological and pathological conditions. In this study, we investigated: (i) the expression of EGFL7 and its miR-126 in patients affected by diffuse cutaneous SSc (dcSSc); (ii) the ability of Transforming Growth Factor-beta (TGF-β) to modulate EGFL7 expression; (iii) the ability of EGFL7 to modulate COL1A1 expression and proliferation/migration, and (iv) the functional role of EGFL7 on angiogenesis. Patients were divided in 2 subsets: patients fulfilling the classification criteria in less than one year from Raynaud’s Phenomenon onset (Early Onset Subset–EOS), and all the others (Long Standing Subset–LSS). We show that EGFL7 expression is increased in EOS dcSSc skin and cultured FBs. EGFL7 is inducible by TGF-β on Healthy Controls (HC) FBs but not in SSc-FBs. EGFL7 decreases COL1A1 expression in EOS SSc-FBs while EGFL7 silencing up-regulates COL1A1 expression. EGFL7 promotes migration/invasion of EOS SSc-FBs but not proliferation. Finally, SSc-FBs, partially inhibit angiogenesis in organotypic coculture assays, and this is reversed by treatment with human recombinant (rh)EGFL7. We conclude that EGFL7 and its specific microRNA miR-126 may be involved in the pathogenesis of SSc vasculopathy and fibrosis.

Nanomedicine and advanced technologies for burns: Preventing infection and facilitating wound healing

According to the latest report from the World Health Organization, an estimated 265,000 deaths still occur every year as a direct result of burn injuries. A widespread range of these deaths induced by burn wound happens in low- and middle-income countries, where survivors face a lifetime of morbidity. Most of the deaths occur due to infections when a high percentage of the external regions of the body area is affected. Microbial nutrient availability, skin barrier disruption, and vascular supply destruction in burn injuries as well as systemic immunosuppression are important parameters that cause burns to be susceptible to infections. Topical antimicrobials and dressings are generally employed to inhibit burn infections followed by a burn wound therapy, because systemic antibiotics have problems in reaching the infected site, coupled with increasing microbial drug resistance. Nanotechnology has provided a range of molecular designed nanostructures (NS) that can be used in both therapeutic and diagnostic applications in burns. These NSs can be divided into organic and non-organic (such as polymeric nanoparticles (NPs) and silver NPs, respectively), and many have been designed to display multifunctional activity. The present review covers the physiology of skin, burn classification, burn wound pathogenesis, animal models of burn wound infection, and various topical therapeutic approaches designed to combat infection and stimulate healing. These include biological based approaches (e.g. immune-based antimicrobial molecules, therapeutic microorganisms, antimicrobial agents, etc.), antimicrobial photo- and ultrasound-therapy, as well as nanotechnology-based wound healing approaches as a revolutionizing area. Thus, we focus on organic and non-organic NSs designed to deliver growth factors to burned skin, and scaffolds, dressings, etc. for exogenous stem cells to aid skin regeneration. Eventually, recent breakthroughs and technologies with substantial potentials in tissue regeneration and skin wound therapy (that are as the basis of burn wound therapies) are briefly taken into consideration including 3D-printing, cell-imprinted substrates, nano-architectured surfaces, and novel gene-editing tools such as CRISPR-Cas.