Endothelial Cell Growth Research Articles

Microneedle Patch for Transdermal Sequential Delivery of KGF-2 and aFGF to Enhance Burn Wound Therapy.

Severe burn wounds usually destroy key cells' functions of the skin resulting in delayed re-epithelization and wound regeneration. Promoting key cells' activities is crucial for burn wound repair. It is well known that keratinocyte growth factor-2 (KGF-2) participates in the proliferation and morphogenesis of epithelial cells while acidic fibroblast growth factor (aFGF)is a key mediator for fibroblast and endothelial cell growth and differentiation. However, thick eschar and the harsh environment of a burn wound often decrease the delivery efficiency of fibroblast growth factor (FGF) to the wound site. Therefore, herein a novel microneedle patch for sequential transdermal delivery of KGF-2 and aFGF is fabricated to enhance burn wound therapy. aFGF is first loaded in the nanoparticle (NPaFGF) and then encapsulated NPaFGF with KGF-2 in the microneedle patch (KGF-2/NPaFGF@MN). The result shows that KGF-2/NPaFGF@MN can successfully get across the eschar and sequentially release KGF-2 and aFGF. Additional data demonstrated that KGF-2/NPaFGF@MN achieved a quicker wound closure rate with reduced necrotic tissues, faster re-epithelialization, enhanced collagen deposition, and increased neo-vascularization. Further evidence suggests that improved wound healing is regulated by significantly elevated expressions of hypoxia-inducible factor-1 alpha(HIF-1ɑ) and heat shock protein 90 (Hsp90) in burn wounds. All these data proved that KGF-2/NPaFGF@MN is an effective treatment for wound healing of burns.

Reagent‐Free Covalent Immobilization of Biomolecules in a Microfluidic Organ‐On‐A‐Chip

AbstractMicrofluidic systems have become integral for lab‐on‐a‐chip and organ‐on‐a‐chip applications across numerous disciplines. These systems, typically fabricated using polydimethylsiloxane (PDMS) chips on glass substrates, lack the bioactivity required for such applications. To overcome this, biomolecules are immobilized using either oxygen (O2) plasma treatment or chemical reagents like amino silanes. However, O2 plasma treatments are unstable and cannot covalently immobilize biomolecules, while wet‐chemistry approaches are toxic, time‐consuming, and expensive. A novel microfluidic platform that combines two plasma surface treatments: Plasma‐activated coating (PAC) and atmospheric pressure plasma jet (APPJ), to enable reagent‐free covalent immobilization of biomolecules is described here. These surface treatments, unlike O2 plasma, covalently immobilized fibronectin on PDMS and glass, and significantly improved endothelial cell attachment and proliferation. By combining PAC and APPJ, a hybrid microfluidic platform with equivalent bond strength to standard O2 plasma devices, but with significantly enhanced endothelial cell growth in and artery‐on‐a‐chip model, is developed. This platform is also amenable to high‐shear applications such as coronary shear, with endothelial cells aligning with flow, as seen in human arteries. By providing reagent‐free covalent immobilization of biomolecules within a microfluidic system, this technology has the potential to radically improve organ‐on‐a‐chip development as well as lab‐on‐a‐chip systems, point‐of‐care diagnostics, and sensors.

Identification of Key Genes in Angiogenesis of Breast and Prostate Cancers in the Context of Different Cell Types.

Angiogenesis involves the development of new blood vessels. Biochemical signals start this process in the body, which is followed by migration, growth, and differentiation of endothelial cells that line the inside wall of blood vessels. This process is vital for the growth of cancer cells and tumors. We started our analysis by composing a list of genes that have a validated impact in humans with respect to angiogenesis-related phenotypes. Here, we have investigated the expression patterns of angiogenesis-related genes in the context of previously published single-cell RNA-Seq data from prostate and breast cancer samples. Using a protein-protein interaction network, we showed how different modules of angiogenesis-related genes are overexpressed in different cell types. In our results, genes, such as ACKR1, AQP1, and EGR1, showed a strong cell type-dependent overexpression pattern in the two investigated cancer types, which can potentially be helpful in the diagnosis and follow-up of patients with prostate and breast cancer. Our work demonstrates how different biological processes in distinct cell types contribute to the angiogenesis process, which can provide clues regarding the potential application of targeted inhibition of the angiogenesis process.

Methacrylated gelatin hydrogel conjugated with ε-polylysine and enriched with platelet-rich plasma for chronically infected wounds

While numerous hydrogel dressings are available for treating chronically infected wounds, their clinical application is impeded by intricate preparation processes, low mechanical strength, and frequent reliance on exogenous antimicrobial agents. The latter often leads to antibiotic misuse and compromises the bioactivity of cell growth-promoting substances. Therefore, the field of therapeutic treatment is faced with a pressing need to prepare high-mechanical-strength hydrogels through a facile procedure, achieving endogenous antibacterial characteristics and long-term healing abilities for chronically infected wounds. In this study, employing the Michael addition reaction principle, we conducted the conjugate addition of the natural antimicrobial poly amino acid, ε-polylysine (ε-PL), to gelatin methacrylate. This not only augmented the hydrogel’s mechanical strength but also preserved its antimicrobial efficacy. Subsequently, platelet-rich plasma (PRP), capable of releasing diverse growth factors, was introduced. Injectable and degradable hydrogels with high mechanical strength and water absorption were prepared through UV curing while retaining PRP bioactivity. The combination of PRP and ε-PL substantiated the enhanced antimicrobial properties and promotion of human umbilical vein endothelial cell growth, as validated through bacterial inhibition experiments, such as live-dead bacterial staining and cellular assays, including cell proliferation. Therefore, the as-developed PL-PRP hydrogel presents as a promising hydrogel dressing for the treatment of chronically infected wounds.

Insights from the SNP analysis of TYMP gene linking MNGIE.

TYMP gene, which codes for thymidine phosphorylase (TP) is also known as platelet-derived endothelial cell growth factor (PD-ECGF). TP plays crucial roles in nucleotide metabolism and angiogenesis. Mutations in the TYMP gene can lead to Mitochondrial Neurogastrointestinal Encephalopathy (MNGIE) syndrome, a rare genetic disorder. Our main objective was to evaluate the impact of detrimental non-synonymous single nucleotide polymorphisms (nsSNPs) on TP protein structure and predict harmful variants in untranslated regions (UTR). We employed a combination of predictive algorithms to identify nsSNPs with potential deleterious effects, followed by molecular modeling analysis to understand their effects on protein structure and function. Using 13 algorithms, we identified 119 potentially deleterious nsSNPs, with 82 located in highly conserved regions. Of these, 53 nsSNPs were functional and exposed, while 79 nsSNPs reduced TP protein stability. Further analysis of 18 nsSNPs through 3D protein structure analysis revealed alterations in amino acid interactions, indicating their potential impact on protein function. This will help in the development of faster and more efficient genetic tests for detecting TYMP gene mutations.

Abstract 5394: Nicotine-induced exosomal miR-3157-3p from prostate cancer cells promotes angiogenesis

Abstract Nicotine is a psychoactive component of cigarette smoke responsible for addictive properties of tobacco and is shown to promote cancer pathogenesis. We earlier reported that exosomes released from nicotine-treated prostate cancer cells played a key role in tumor angiogenesis, a process necessary to maintain the supply of nutrients and oxygen to the fast proliferating cancer cells. Here, we examined the molecular mechanisms underlying the exosome-mediated effect of nicotine on angiogenesis. For this, we screened the expression of angiogenesis-related miRNAs in the exosomes derived from LNCaP and C4-2 cells treated with vehicle or nicotine (400 nM). Highest and most differential abundance of miR-3157-3p was found in exosomes derived from nicotine-treated prostate cancer cells. Furthermore, the expression of TIMP-2 and KLF-2, established targets of miR-3157-3p, was also downregulated in endothelial cells transfected with exosomes derived from nicotine-treated prostate cancer cells or miR-3157-3p mimics. Studies are currently underway to establish direct targeting of TIMP-2 and KLF-2 by miR-3157-3p and confirm that their suppression is indeed associated with observed changes in endothelial cell growth, migration and capillary-forming ability. Citation Format: Shubhangi Singh, Mohammad Aslam Khan, Shashi Anand, Sirin Saranyutanon, Sanjeev Kumar Srivastava, Seema Singh, Ajay P. Singh, Kunwar Somesh Vikramdeo. Nicotine-induced exosomal miR-3157-3p from prostate cancer cells promotes angiogenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5394.

Abstract 2734: RC148, a novel bispecific antibody targeting PD-1 and VEGF for cancer immunotherapy

Abstract Vascular endothelial growth factor (VEGF) is one of the most important pro-angiogenic factors in modulating tumor microenvironment (TME), and the concentration of VEGF in TME is significantly higher than that of peripheral. Inhibiting VEGF can improve immunotherapy efficacy by modulating the TME, preventing angiogenesis and regulating immune cell populations. Combined anti-VEGF and anti-Programmed cell death protein 1 (PD-1)/Programmed cell death ligand (PD-L1) therapies have exerted potent antitumor effect in preclinic and clinic studies. Therefore, we developed a novel humanized IgG1 silenced bispecific antibody RC148 to target VEGF and PD-1. RC148 allows dimeric VEGF crosslinking and gradually enhances PD-1 binding activity, potentially reduces systemic toxicity of anti-VEGF therapy and enhances antitumor potency via VEGF trigged enrichment in tumor areas. In preclinical studies, RC148 blocks the binding of VEGF to VEGFR and PD-1 to PD-L1, prevents the growth and migration of human umbilical vein endothelial cells, enables efficient T cell activation, exhibited synergistic antitumor effects in rodent models and showed safety profiles in non-human primate studies. Citation Format: Jianmin Fang, Dong Li, Kaiyue Wu, Sisi Wang, Du Li, Guorui Zhao, Shenjun Li, Jing Jiang. RC148, a novel bispecific antibody targeting PD-1 and VEGF for cancer immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2734.

Abstract 5385: Synthetic disulfide derivative of vitamin B1, fursultiamine, prevents VEGF-induced angiogenesis

Abstract Angiogenesis is a process in which new blood vessels are formed from the existing blood vessels required to supply nutrients and oxygen to various tissues. Angiogenesis plays a significant role in the growth and spread of many cancers, and several anti-angiogenic agents act as chemotherapeutic agents. Recent studies have shown that fursultiamine (thiamine tetrahydrofurfuryl disulfide), a lipid-soluble synthetic disulfide derivative of thiamine, possesses viable antineoplastic and antiviral effects. However, its role in preventing angiogenesis is not known. We hypothesize that fursultiamine, with its potent antioxidative actions, prevents VEGF-induced angiogenesis in vitro and in vivo. Human umbilical vein endothelial cells (HUVECs) were treated with VEGF in the absence and presence of fursultiamine (0-100 uM) in a time and dose-dependent manner. Cell viability was determined by MTT assay and in vitro angiogenesis by tube formation assays. The expression of various pro-angiogenic, anti-angiogenic and inflammatory markers will be determined by specific antibody arrays. Our results indicate that fursultiamine prevents VEGF-induced endothelial cell growth in a dose-dependent manner. Further, fursultiamine prevents the in vitro tube formation as determined tube formation assays. Further, fursultiamine also regulated the VEGF-induced expression of various angiogenic markers such as VEGF, PDGF, EGF, Ang1, Ang2, angiogenin, and FGF, inflammatory markers such IL-1b, GM-CSF, TGF-b, MMPs, and others such as TIMPs, PTX3 and CF-III. Based on our in vitro data, we suggest that fursultiamine could prevent VEGF-induced angiogenesis, and this compound as a potent anti-angiogenic agent that could prevent cancer growth and metastasis. Citation Format: Sabrina Tran, Zachary Frost, Kota Ramana. Synthetic disulfide derivative of vitamin B1, fursultiamine, prevents VEGF-induced angiogenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5385.

Mutations causing premature termination codons discriminate and generate cellular and clinical variability in HHT

AbstractFor monogenic diseases caused by pathogenic loss-of-function DNA variants, attention focuses on dysregulated gene-specific pathways, usually considering molecular subtypes together within causal genes. To better understand phenotypic variability in hereditary hemorrhagic telangiectasia (HHT), we subcategorized pathogenic DNA variants in ENG/endoglin, ACVRL1/ALK1, and SMAD4 if they generated premature termination codons (PTCs) subject to nonsense-mediated decay. In 3 patient cohorts, a PTC-based classification system explained some previously puzzling hemorrhage variability. In blood outgrowth endothelial cells (BOECs) derived from patients with ACVRL1+/PTC, ENG+/PTC, and SMAD4+/PTC genotypes, PTC-containing RNA transcripts persisted at low levels (8%-23% expected, varying between replicate cultures); genes differentially expressed to Bonferroni P < .05 in HHT+/PTC BOECs clustered significantly only to generic protein terms (isopeptide-bond/ubiquitin-like conjugation) and pulse-chase experiments detected subtle protein maturation differences but no evidence for PTC-truncated protein. BOECs displaying highest PTC persistence were discriminated in unsupervised hierarchical clustering of near-invariant housekeeper genes, with patterns compatible with higher cellular stress in BOECs with >11% PTC persistence. To test directionality, we used a HeLa reporter system to detect induction of activating transcription factor 4 (ATF4), which controls expression of stress-adaptive genes, and showed that ENG Q436X but not ENG R93X directly induced ATF4. AlphaFold accurately modeled relevant ENG domains, with AlphaMissense suggesting that readthrough substitutions would be benign for ENG R93X and other less rare ENG nonsense variants but more damaging for Q436X. We conclude that PTCs should be distinguished from other loss-of-function variants, PTC transcript levels increase in stressed cells, and readthrough proteins and mechanisms provide promising research avenues.

Umbilical blood as a trophic-growth supplement for cultural work

This review analyzes the results of modern high-tech research on the use of umbilical cord blood serum/plasma as an additive to culture media for cell culture growth. Since culture media are a key factor in cell culture, the review addresses the composition and properties of the major culture media used in cell biology and regenerative medicine. The authors pay special attention to growth factors; they describe the functional properties of the main families of these polypeptides (fibroblast growth factors, epidermal growth factors, transforming growth factors, differentiation growth factors, epidermal growth factors, endothelial cell growth factors, hematopoietic growth factors, etc.). It was found that one of the most promising sources of growth factors is cord blood serum/plasma. In this publication, the main technologies for cord blood collection and systematic studies on the content of growth factors, cytokines, exosomes and mRNA in cord blood are presented. Experimental data on the use of umbilical cord blood serum/plasma as an additive to culture media for the growth of various cell cultures of animal origin are described. Human umbilical cord blood serum/plasma is an affordable, safe product with a high content of biologically active molecules compared to animal sources. In order for umbilical cord blood serum/plasma to be widely used as an adjunct to culture media, standards for the manufacture and testing of this product must be developed.

Brain Organoids, the Path Forward?

Brain Organoids, the Path Forward?

Rickettsia rickettsii virulence determinants RARP2 and RapL mitigate IFN-β signaling in primary human dermal microvascular endothelial cells.

We compared the growth characteristics of a virulent Rickettsia rickettsii strain (Sheila Smith) to an attenuated R. rickettsii stain (Iowa) and a non-pathogenic species (R. montanensis) in primary human dermal microvascular endothelial cells (HDMEC). All replicated in Vero cells, however, only the Sheila Smith strain productively replicated in HDMECs. The Iowa strain showed minimal replication over a 24-h period, while R. montanensis lost viability and induced lysis of the HDMECs via a rapid programmed cell death response. Both the virulent and attenuated R. rickettsii strains, but not R. montanensis, induced an interferon-1 response, although the response was of lesser magnitude and delayed in the Sheila Smith strain. IFN-β secretion correlated with increased host cell lysis, and treatment with anti-IFNAR2 antibody decreased lysis from Iowa-infected but not Sheila Smith-infected cells. Both Sheila Smith- and Iowa-infected cells eventually lysed, although the response from Sheila Smith was delayed and showed characteristics of apoptosis. We, therefore, examined whether reconstitution of the Iowa strain with two recently described putative virulence determinants might enhance survival of Iowa within HDMECs. Reconstitution with RARP2, which is inhibitory to anterograde trafficking through the Golgi apparatus, reduced IFN-β secretion but had no effect on cell lysis. RapL, which proteolytically processes surface exposed autotransporters and enhances replication of Iowa in Guinea pigs, suppressed both IFN-β production and host cell lysis. These findings suggest distinct mechanisms by which virulent spotted fever group rickettsiae may enhance intracellular survival and replication.IMPORTANCEWe examined a naturally occurring non-pathogenic rickettsial species, R. montanensis, a laboratory-attenuated R. rickettsii strain (Iowa), and a fully virulent R. rickettsii strain (Sheila Smith) for growth in human dermal microvascular endothelial cells. The two avirulent strains replicated poorly or not at all. Only the virulent Sheila Smith strain replicated. IFN-β production correlated with the inhibition of R. rickettsii Iowa. Reconstitution of Iowa with either of two recently described putative virulence determinants altered the IFN-β response. A rickettsial ankyrin repeat protein, RARP2, disrupts the trans-Golgi network and inhibits IFN-β secretion. An autotransporter peptidase, RapL, restores proteolytic maturation of outer membrane autotransporters and diminishes the IFN-β response to enhance cell survival and permit replication of the recombinant strain. These studies point the way toward discovery of mechanisms for innate immune response avoidance by virulent rickettsia.

Synthesis of Injectable Thermosensitive Cinnamaldehyde-Loaded Chitosan Hydrogel for Antibacterial and Wound Dressing Application

The wound healing in the presence of bacterial infections is a complex process and prolonged challenge with severe implications for human health. To address this issue, injectable thermo-sensitive hydrogels as wound dressings have garnered considerable attention as a potential solution. In this study, we have developed an injectable and antibacterial thermosensitive hydrogel for wound healing, based on chitosan (CS) and β-glycerophosphate (β-GP) and modified with a range of cinnamaldehyde (CA). The CS/β-GP/CA gels demonstrate a phase transition at body temperatures, and exhibit good biocompatibility. Compared with the unmodified CS/β-GP hydrogels, incorporating CA can promote endothelial cell growth and the antibacterial property of the hydrogel system, which may lead to faster wound healing and tissue regeneration. Our findings suggest that the CS/β-GP/CA thermosensitive hydrogel emerges as a promising candidate for an injectable wound dressing in wound treatments.

Vascularized organoid-on-a-chip: design, imaging, and analysis.

Vascularized organoid-on-a-chip (VOoC) models achieve substance exchange in deep layers of organoids and provide a more physiologically relevant system in vitro. Common designs for VOoC primarily involve two categories: self-assembly of endothelial cells (ECs) to form microvessels and pre-patterned vessel lumens, both of which include the hydrogel region for EC growth and allow for controlled fluid perfusion on the chip. Characterizing the vasculature of VOoC often relies on high-resolution microscopic imaging. However, the high scattering of turbid tissues can limit optical imaging depth. To overcome this limitation, tissue optical clearing (TOC) techniques have emerged, allowing for 3D visualization of VOoC in conjunction with optical imaging techniques. The acquisition of large-scale imaging data, coupled with high-resolution imaging in whole-mount preparations, necessitates the development of highly efficient analysis methods. In this review, we provide an overview of the chip designs and culturing strategies employed for VOoC, as well as the applicable optical imaging and TOC methods. Furthermore, we summarize the vascular analysis techniques employed in VOoC, including deep learning. Finally, we discuss the existing challenges in VOoC and vascular analysis methods and provide an outlook for future development.

A comparison of endothelial cell growth on commercial coronary stents with and without laser surface texturing

Complete endothelialisation of coronary stents is an important determinant of future thrombotic complications following coronary stenting. Stent surface texture is an important factor that influences endothelial cell growth. With the emergence of second and third generation coronary stents, is limited comparative data describing endothelial cell growth in contemporary stent platforms, and limited data available on approaches used to rapidly modify the surfaces of commercial coronary stents to improve endothelialisation. In this study we have determined the in vitro proliferation of the primary human coronary artery endothelial cells on the commonly used 4 types of commercial coronary stents and found that the inner surface of BioMatrix drug-eluting stents (DES), after eliminating of the polymer and drug coating, had significantly higher endothelial cell proliferation compared to that of other bare metal stents (BMS): Multi-Link8, Integrity and Omega. The surfaces of the 3 types of BMS which are smooth, displayed similar endothelial cell proliferation, suggesting the importance of surface features in manipulating endothelial cell growth. Laser surface texturing was used to create micro/nano patterns on the stents. The laser treatment has significantly increased endothelial proliferation on the inner surfaces of all 4 types of stents, and Multi-Link8 stents displayed the highest (>100%) improvement. The laser textured BioMatrix stents had the highest absolute number of endothelial cells growth. Our results provided useful information in the endothelialisation potential for the commonly used commercial coronary stents and suggested a potential future application of laser surface bioengineering to coronary stents for better biocompatibility of the device.

MicroRNA-409-3p/BTG2 signaling axis improves impaired angiogenesis and wound healing in obese mice.

Wound healing is facilitated by neoangiogenesis, a complex process that is essential to tissue repair in response to injury. MicroRNAs are small, noncoding RNAs that can regulate the wound healing process including stimulation of impaired angiogenesis that is associated with type-2 diabetes (T2D). Expression of miR-409-3p was significantly increased in the nonhealing skin wounds of patients with T2D compared to the non-wounded normal skin, and in the skin of a murine model with T2D. In response to high glucose, neutralization of miR-409-3p markedly improved EC growth and migration in human umbilical vein endothelial cells (HUVECs), promoted wound closure and angiogenesis as measured by increased CD31 in human skin organoids, while overexpression attenuated EC angiogenic responses. Bulk mRNA-Seq transcriptomic profiling revealed BTG2 as a target of miR-409-3p, where overexpression of miR-409-3p significantly decreased BTG2 mRNA and protein expression. A 3' untranslated region (3'-UTR) luciferase assay of BTG2 revealed decreased luciferase activity with overexpression of miR-409-3p, while inhibition had opposite effects. Mechanistically, in response to high glucose, miR-409-3p deficiency in ECs resulted in increased mTOR phosphorylation, meanwhile BTG-anti-proliferation factor 2 (BTG2) silencing significantly decreased mTOR phosphorylation. Endothelial-specific and tamoxifen-inducible miR-409-3p knockout mice (MiR-409IndECKO ) with hyperglycemia that underwent dorsal skin wounding showed significant improvement of wound closure, increased blood flow, granulation tissue thickness (GTT), and CD31 that correlated with increased BTG2 expression. Taken together, our results show that miR-409-3p is a critical mediator of impaired angiogenesis in diabetic skin wound healing.

Bee Venom Stimulates Growth Factor Release from Adipose-Derived Stem Cells to Promote Hair Growth.

Limited evidence suggests that stimulating adipose-derived stem cells (ASCs) indirectly promotes hair growth. We examined whether bee venom (BV) activated ASCs and whether BV-induced hair growth was facilitated by enhanced growth factor release by ASCs. The induction of the telogen-to-anagen phase was studied in mice. The underlying mechanism was investigated using organ cultures of mouse vibrissa hair follicles. When BV-treated ASCs were injected subcutaneously into mice, the telogen-to-anagen transition was accelerated and, by day 14, the hair weight increased. Quantitative polymerase chain reaction (qPCR) revealed that BV influenced the expression of several molecules, including growth factors, chemokines, channels, transcription factors, and enzymes. Western blot analysis was employed to verify the protein expression levels of extracellular-signal-regulated kinase (ERK) and phospho-ERK. Both the Boyden chamber experiment and scratch assay confirmed the upregulation of cell migration by BV. Additionally, ASCs secreted higher levels of growth factors after exposure to BV. Following BV therapy, the gene expression levels of alkaline phosphatase (ALP), fibroblast growth factor (FGF)-1 and 6, endothelial cell growth factor, and platelet-derived growth factor (PDGF)-C were upregulated. The findings of this study suggest that bee venom can potentially be utilized as an ASC-preconditioning agent for hair regeneration.

Retracted: Loading Gentamicin and Zn2+ on TiO2 Nanotubes to Improve Anticoagulation, Endothelial Cell Growth, and Antibacterial Activities.

[This retracts the article DOI: 10.1155/2021/9993247.].

Silica nanoparticles enhance the cyto- and hemocompatibility of a multilayered extracellular matrix scaffold for vascular tissue regeneration.

The limited availability of autologous vessels for vascular bypass surgeries is a major roadblock to treating severe cardiovascular diseases. Based on this clinical priority, our group has developed a novel engineered vascular graft by rolling human amniotic membranes into multilayered extracellular matrixes (ECM). When treated with silica nanoparticles (SiNP), these rolled scaffolds showed a significant improvement in their structural and mechanical properties, matching those from gold standard autologous grafts. However, it remained to be determined how cells respond to SiNP-treated materials. As a first step toward understanding the biocompatibility of SiNP-dosed biomaterials, we aimed to assess how endothelial cells and blood components interact with SiNP-treated ECM scaffolds. To test this, we used established in vitro assays to study SiNP and SiNP-treated scaffolds' cyto and hemocompatibility. Our results showed that SiNP effects on cells were concentration-dependent with no adverse effects observed up to 10μg/ml of SiNP, with higher concentrations inducing cytotoxic and hemolytic responses. The SiNP also enhanced the scaffold's hydrophobicity state, a feature known to inhibit platelet and immune cell adhesion. Accordingly, SiNP-treated scaffolds were also shown to support endothelial cell growth while preventing platelet and leukocyte adhesion. Our findings suggest that the addition of SiNP to human amniotic membrane extracellular matrixes improves the cyto- and hemocompatibility of rolled scaffolds and highlights this strategy as a robust mechanism to stabilize layered collagen scaffolds for vascular tissue regeneration.

Enhancement of de novo lipogenesis by the IDH1 and IDH2-dependent reverse TCA cycle maintains the growth and angiogenic capacity of bone marrow-derived endothelial progenitor cells under hypoxia

BackgroundBone marrow-derived endothelial progenitor cells (EPCs) play a dynamic role in maintaining the structure and function of blood vessels. But how these cells maintain their growth and angiogenic capacity under bone marrow hypoxic niche is still unclear. This study aims to explore the mechanisms from a perspective of cellular metabolism. MethodsXFe96 Extracellular Flux Analyzer was used to analyze the metabolic status of EPCs. Gas Chromatography-Mass Spectrometry (GC-MS) was used to trace the carbon movement of 13C-labeled glucose and glutamine under 1 % O2 (hypoxia) and ∼20 % O2 (normoxia). Moreover, RNA interference, targeting isocitrate dehydrogenase-1 (IDH1) and IDH2, was used to inhibit the reverse tricarboxylic acid (TCA) cycle and analyze metabolic changes via isotope tracing as well as changes in cell growth and angiogenic potential under hypoxia. The therapeutic potential of EPCs under hypoxia was investigated in the ischemic hindlimb model. ResultsCompared with normoxic cells, hypoxic cells showed increased glycolysis and decreased mitochondrial respiration. Isotope metabolic tracing revealed that under hypoxia, the forward TCA cycle was decreased and the reverse TCA cycle was enhanced, mediating the conversion of α-ketoglutarate (α-KG) into isocitrate/citrate, and de novo lipid synthesis was promoted. Downregulation of IDH1 or IDH2 under hypoxia suppressed the reverse TCA cycle, attenuated de novo lipid synthesis (DNL), elevated α-KG levels, and decreased the expression of hypoxia inducible factor-1α (HIF-1α) and vascular endothelial growth factor A (VEGFA), eventually inhibiting the growth and angiogenic capacity of EPCs. Importantly, the transplantation of hypoxia-cultured EPCs in a mouse model of limb ischemia promoted new blood vessel regeneration and blood supply recovery in the ischemic area better than the transplantation of normoxia-cultured EPCs. ConclusionsUnder hypoxia, the IDH1- and IDH2-mediated reverse TCA cycle promotes glutamine-derived de novo lipogenesis and stabilizes the expression of α-KG and HIF-1α, thereby enhancing the growth and angiogenic capacity of EPCs.