Main Components Of Extracellular Matrix Research Articles

Impact of changes in collagen construction and molecular state on integrin – binding properties

The interaction between the integrin and collagen is important in cell adhesion and signaling. Collagen, as the main component of extracellular matrix, is a base material for tissue engineering constructs. In tissue engineering, the collagen structure and molecule state may be altered to varying degrees in the process of processing and utilizing, thereby affecting its biological properties. In this work, the impact of changes in collagen structure and molecular state on the binding properties of collagen to integrin α2β1 and integrin specific cell adhesion were explored. The results showed that the molecular structure of collagen is destroyed under the influence of heating, freeze-grinding and irradiation, the triple helix integrity is reduced and molecular breaking degree is increased. The binding ability of collagen to integrin α2β1 is increased with the increase of triple helix integrity and decays exponentially with the increase of molecular breaking degree. The collagen molecular state can also influences the binding ability of collagen to cellular receptor. The collagen fibrils binding to integrin α2β1 and HT1080 cells is stronger than to collagen monomolecule. Meanwhile, the hybrid fibril exhibits a different cellular receptor binding performance from corresponding single species collagen fibril. These findings provide ideas for the design and development of new collagen-based biomaterials and tissue engineering research.

Renal denervation restores biomechanics of carotid arteries in a rat model of hypertension

The prevalence of hypertension increases with aging and is associated with increased arterial stiffness. Resistant hypertension is presented when drug treatments fail to regulate a sustained increased blood pressure. Given that the mechanisms between the sympathetic nervous system and the kidney play an important role in blood regulation, renal denervation (RDN) has emerged as a therapeutic potential in resistant hypertension. In this study, we investigated the effects of RDN on the biomechanical response and microstructure of elastic arteries. Common carotid arteries (CCA) excised from 3-month, 8-month, and 8-month denervated rats were subjected to biaxial extension-inflation test. Our results showed that hypertension developed in the 8-month-old rats. The sustained elevated blood pressure resulted in arterial remodeling which was manifested as a significant stress increase in both axial and circumferential directions after 8 months. RDN had a favorable impact on CCAs with a restoration of stresses in values similar to control arteries at 3 months. After biomechanical testing, arteries were imaged under a multi-photon microscope to identify microstructural changes in extracellular matrix (ECM). Quantification of multi-photon images showed no significant alterations of the main ECM components, elastic and collagen fibers, indicating that arteries remained intact after RDN. Regardless of the experimental group, our microstructural analysis of the multi-photon images revealed that reorientation of the collagen fibers might be the main microstructural mechanism taking place during pressurization with their straightening happening during axial stretching.

Tunable biomimetic materials elaborated by ice templating and self-assembly of collagen for tubular tissue engineering.

Synthetic tubular grafts currently used in clinical context fail frequently, and the expectations that biomimetic materials could tackle these limitations are high. However, developing tubular materials presenting structural, compositional and functional properties close to those of native tissues remains an unmet challenge. Here we describe a combination of ice templating and topotactic fibrillogenesis of type I collagen, the main component of tissues' extracellular matrix, yielding highly concentrated yet porous tubular collagen materials with controlled hierarchical architecture at multiple length scales, the hallmark of native tissues' organization. By modulating the thermal conductivity of the cylindrical molds, we tune the macroscopic porosity defined by ice. Coupling the aforementioned porosity patterns with two different fibrillogenesis routes results in a new family of tubular materials whose textural features and the supramolecular arrangement of type I collagen are achieved. The resulting materials present hierarchical elastic properties and are successfully colonized by human endothelial cells and alveolar epithelial cells on the luminal side, and by human mesenchymal stem cells on the external side. The proposed straightforward protocol is likely to be adapted for larger graft sizes that address ever-growing clinical needs, such as peripheral arterial disease or tracheal and bronchial reconstructions.

Fabrication and In Vitro Characterization of Polycaprolactone/Graphene Oxide/Collagen Nanofibers for Myocardial Repair

AbstractThis study is focused on fabricating tissue‐engineered electrospun nanofibers that contain polycaprolactone (PCL), graphene oxide (GO), and collagen (COL) to get an alternative treatment for cardiac injuries. GO (1.5 wt%) is used to support the contraction‐elongation of cardiomyocytes by improving electrical stimulation. The COL (1, 3, and 5 wt%) is the main component of the myocardial extracellular matrix have led to their frequent use in cardiac tissue engineering (CTE). The scanning electron microscope (SEM) images show the homogeneous and bead‐free morphologies of the nanofibers. Adding a high amount (3% and 5%) of COL decreases the tensile strength value of 17% PCL/1.5% GO nanofiber. 3‐(4,5‐Dimethylthiazol‐2‐yl)‐2,5‐Diphenyltetrazolium Bromide (MTT) assay demonstrates that the COL addition increases cell viability compared to that in 17% PCL/1.5% GO nanofibers on the third day. The response of the nanofibers to alternating current (AC) signal is studied between the frequencies 40 and 105 Hz. The direct current (DC) conductivity values of the films are determined to be between 1.10−10 and 6.10−10 S m−1 at 25 °C. The AC conductivity values show frequency‐dependent behavior. Among the PCL/GO‐based electrospun nanofibers, 17% PCL/1.5% GO/5% COL nanofiber shows greater DC and AC conductivity than 17% PCL/1.5% GO nanofiber.

Collagen study advances for photoaging skin.

Collagen dominates the skin's extracellular matrix (ECM). Type I collagen comprises 80%-90% of the skin's collagen, followed by type III (8%-12%) and type V (5%). Reactive oxygen species, matrix metalloproteinases, and collagen degradation all increase during photoaging, which disrupts the ECM's dynamic balance and lowers the amount of total collagen in the body. In recent years, domestic and foreign researchers have conducted multidimensional and multifaceted studies on collagen and skin photoaging. Collagen and the peptides that are derivates of it are currently being used more and more in biomedicine and medical esthetics. Offering new suggestions for both the avoidance and remedy of photoaging. This article reviews collagen and its potential connection to skin photoaging, illustrates the effects of collagen and peptide supplementation derivatives on photoaged skin, and briefly describes other compounds that can also be used to fight photoaging by increasing collagen synthesis in the skin. Both internal and external aging are inevitable, and as the main component of extracellular matrix, collagen plays a variety of functions in maintaining skin structure and fighting skin aging, and its role in photoaging is undeniable. Ultraviolet radiation can induce increased fragmentation and degradation of cutaneous collagen, while conversely, supplementation with collagen can effectively counteract photodamage-induced skin impairment. Collagen and its derived peptides are indispensable in photoaging skin, holding promising prospects for applications in skin aging.

Chondroitin Sulfate Improves Mechanical Properties of Gelatin Hydrogel for Cartilage Regeneration in Rats.

Cartilage injury is a common disease in daily life. Especially in aging populations, the incidence of osteoarthritis is increasing. However, due to the poor regeneration ability of cartilage, most cartilage injuries cannot be effectively repaired. Even cartilage tissue engineering still faces many problems such as complex composition and poor integration of scaffolds and host tissues. In this study, chondroitin sulfate, one of the main components of extracellular matrix (ECM), is chosen as the main natural component of the material, which can protect cartilage in a variety of ways. Moreover, the results show that the addition of chondroitin sulfate improves the mechanical properties of gelatin methacrylate (GelMA) hydrogel, making it able to effectively bear mechanical loads in vivo. Further, chondroitin sulfate is modified to obtain the oxidized chondroitin sulfate (OCS) containing aldehyde groups via sodium periodate. This special group improves the interface integration and adhesion ability of the hydrogel to host cartilage tissue through schiff base reactions. In summary, GelMA/OCS hydrogel is a promising candidate for cartilage regeneration with good biocompatibility, mechanical properties, tissue integration ability, and excellent cartilage repair ability.

Osteogenic effects of covalently tethered rhBMP-2 and rhBMP-9 in an MMP-sensitive PEG hydrogel nanocomposite

While bone morphogenic protein-2 (BMP-2) is one of the most widely studied BMPs in bone tissue engineering, BMP-9 has been purported to be a highly osteogenic BMP. This work investigates the individual osteogenic effects of recombinant human (rh) BMP-2 and rhBMP-9, when tethered into a hydrogel, on encapsulated human mesenchymal stem cells (MSCs). A matrix-metalloproteinase (MMP)-sensitive hydrogel nanocomposite, comprised of poly(ethylene glycol) crosslinked with MMP-sensitive peptides, tethered RGD, and entrapped hydroxyapatite nanoparticles was used. The rhBMPs were functionalized with free thiols and then covalently tethered into the hydrogel by a thiol-norbornene photoclick reaction. rhBMP-2 retained its full bioactivity post-thiolation, while the bioactivity of rhBMP-9 was partially reduced. Nonetheless, both rhBMPs were highly effective at enhancing osteogenesis over 12-weeks in a chemically-defined medium. Expression of ID1 and osterix, early markers of osteogenesis; collagen type I, a main component of the bone extracellular matrix (ECM); and osteopontin, bone sialoprotein II and dentin matrix protein I, mature osteoblast markers, increased with increasing concentrations of tethered rhBMP-2 or rhBMP-9. When comparing the two BMPs, rhBMP-9 led to more rapid collagen deposition and greater mineralization long-term. In summary, rhBMP-2 retained its bioactivity post-thiolation while rhBMP-9 is more susceptible to thiolation. Despite this shortcoming with rhBMP-9, both rhBMPs when tethered into this hydrogel, enhanced osteogenesis of MSCs, leading to a mature osteoblast phenotype surrounded by a mineralized ECM. Statement of significanceOsteoinductive hydrogels are a promising vehicle to deliver mesenchymal stem cells (MSCs) for bone regeneration. This study examines the in vitro osteoinductive capabilities when tethered bone morphogenic proteins (BMPs) are incorporated into a degradable biomimetic hydrogel with cell adhesive ligands, matrix metalloproteinase sensitive crosslinks for cell-mediated degradation, and hydroxyapatite nanoparticles. This study demonstrates that BMP-2 is readily thiolated and tethered without loss of bioactivity while bioactivity of BMP-9 is more susceptible to immobilization. Nonetheless, when either BMP2 or BMP9 are tethered into this hydrogel, osteogenesis of human MSCs is enhanced, bone extracellular matrix is deposited, and a mature osteoblast phenotype is achieved. This bone-biomimetic hydrogel is a promising design for stem cell-mediated bone regeneration.

[Intervention of modified Shenling Baizhu San on peritoneal fibrosis induced by peritoneal dialysate with different sugar concentration in rats].

To investigate the effect of modified Shenling Baizhu San on the pathological changes and extracellular matrix (ECM) in rats with peritoneal fibrosis induced by peritoneal dialysate fluid (PDF) with different sugar concentration and its mechanism. Seventy male Sprague-Dawley (SD) rats were randomly divided into control group, different sugar content PDF model groups and corresponding traditional Chinese medicine intervention groups, with 10 rats in each group. Peritoneal fibrosis model was reproduced by intraperitoneal injection of 100 mL×kg-1×d-1 PDF containing 1.5%, 2.5% and 4.25% sugar once a day for 8 weeks. The rats in the control group were given the same amount of normal saline. The rats in the traditional Chinese medicine intervention groups were treated with gavage of 10 mL/kg of modified Shenling Baizhu San (containing 2.014 g crude drug per liter) immediately after modeling. The PDF model groups and the control group were given the same amount of normal saline by gavage. After 8 weeks, the peritoneal ultrafiltration volume of rats in each group was measured. The peritoneal tissues were collected and stained with hematoxylin-eosin (HE), and the structural changes and thickness of the parietal peritoneum were observed under a light microscope. After Masson staining, the deposition of collagen fibers was observed under a light microscope. Western blotting was used to detect the protein expressions of E-cadherin, α-smooth muscle actin (α-SMA) and Vimentin, the main components of ECM in parietal peritoneum. The positive expressions of matrix metalloproteinase-9 (MMP-9), tissue inhibitor of metalloproteinase-1 (TIMP-1), and transforming growth factor-β1 (TGF-β1) were detected by immunohistochemical staining. Compared with the control group, PDF with different sugar contents could induce peritoneal fibrosis in rats, and the degree of fibrosis was gradually aggravated with the increase of sugar content, which was manifested as peritoneal thickening, increased collagen fiber deposition, decreased peritoneal ultrafiltration volume, down-regulated expressions of E-cadherin and MMP-9 in peritoneal tissue, and up-regulated expressions of α-SMA, Vimentin, TIMP-1 and TGF-β1, and the pathological changes and ECM accumulation in peritoneal tissues were more serious in 4.25% PDF model group. After the intervention of modified Shenling Baizhu San, compared with the corresponding PDF model groups, the peritoneal fibrosis of rats was improved to varying degrees, and the effect of the 4.25% PDF+traditional Chinese medicine intervention group was more significant, the parietal peritoneum was significantly thinner (μm: 101.86±16.01 vs. 140.65±10.13, P < 0.05), collagen fiber deposition was significantly reduced, peritoneal ultrafiltration volume was significantly increased (mL: -0.01±3.45 vs. -3.53±1.84, P < 0.05), the expressions of E-cadherin and MMP-9 in peritoneal tissues were significantly up-regulated [E-cadherin protein (E-cadherin/β-actin): 0.84±0.08 vs. 0.28±0.05, MMP-9 (A value): 0.60±0.15 vs. 0.37±0.01, both P < 0.05], and the expressions of α-SMA, Vimentin, TIMP-1 and TGF-β1 were significantly down-regulated [α-SMA protein (α-SMA/β-actin): 0.36±0.08 vs. 1.05±0.09, Vimentin protein (Vimentin/β-actin): 0.53±0.07 vs. 1.19±0.04, TIMP-1 (A value): 0.49±0.06 vs. 0.87±0.02, TGF-β1 (A value): 0.67±0.04 vs. 0.89±0.10, all P < 0.05]. The degree of peritoneal fibrosis gradually increased with the increase of PDF sugar content in rats. Modified Shenling Baizhu San can improve peritoneal fibrosis induced by PDF with different sugar contents in rats, and the mechanism is related to the changes in the expression of fibrosis markers and ECM accumulation.

Unique Biomarkers of Collagen Type III Remodeling Reflect Different Information Regarding Pathological Kidney Tissue Alterations in Patients with IgA Nephropathy.

Kidney fibrosis is the hallmark of chronic kidney disease (CKD) and is characterized by an imbalanced extracellular matrix (ECM) remodeling. Collagen type III is one of the main ECM components of the interstitial matrix of the kidney. We hypothesized that measuring three biomarkers of collagen type III reflecting different aspects of this protein turnover (C3M, C3C, and PRO-C3) may provide different information about the fibrotic burden in patients with IgA nephropathy (IgAN). We examined a cohort of 134 patients with IgAN. The three collagen type III biomarkers were measured in serum (S) and in urine (U) samples taken on the same day before kidney biopsy was performed. Biopsies were evaluated for interstitial fibrosis and tubular atrophy, according to the Banff and MEST-C scores. S-PRO-C3 and S-C3C correlated with the degree of fibrosis in the biopsy, whereas U-C3M/Cr had an inverse correlation with fibrosis. U-C3M/Cr had the highest discrimination ability for advanced fibrosis, which was maintained after adjustment for the other collagen type III biomarkers, proteinuria, and serum creatinine. The data presented in this study indicate that measuring the different fragments of the same ECM protein and in different matrices provides a variety of information regarding pathological kidney tissue alterations in patients with IgAN.

Glycopolypeptide hydrogels with adjustable enzyme-triggered degradation: A novel proteoglycans analogue to repair articular-cartilage defects.

Proteoglycans (PGs), also known as a viscous lubricant, is the main component of the cartilage extracellular matrix (ECM). The loss of PGs is accompanied by the chronic degeneration of cartilage tissue, which is an irreversible degeneration process that eventually develops into osteoarthritis (OA). Unfortunately, there is still no substitute for PGs in clinical treatments. Herein, we propose a new PGs analogue. The Glycopolypeptide hydrogels in the experimental groups with different concentrations were prepared by Schiff base reaction (Gel-1, Gel-2, Gel-3, Gel-4, Gel-5 and Gel-6). They have good biocompatibility and adjustable enzyme-triggered degradability. The hydrogels have a loose and porous structure suitable for the proliferation, adhesion, and migration of chondrocytes, good anti-swelling, and reduce the reactive oxygen species (ROS) in chondrocytes. In vitro experiments confirmed that the glycopolypeptide hydrogels significantly promoted ECM deposition and up-regulated the expression of cartilage-specific genes, such as type-II collagen, aggrecan, and glycosaminoglycans (sGAG). In vivo, the New Zealand rabbit knee articular cartilage defect model was established and the hydrogels were implanted to repair it, the results showed good cartilage regeneration potential. It is worth noting that the Gel-3 group, with a pore size of 122​±​12​μm, was particularly prominent in the above experiments, and provides a theoretical reference for the design of cartilage-tissue regeneration materials in the future.

Heart-derived collagen promotes maturation of engineered heart tissue

Although the extracellular matrix (ECM) plays essential roles in heart tissue engineering, the optimal ECM components for heart tissue organization have not previously been elucidated. Here, we focused on the main ECM component, fibrillar collagen, and analyzed the effects of collagens on heart tissue engineering, by comparing the use of porcine heart-derived collagen and other organ-derived collagens in generating engineered heart tissue (EHT). We demonstrate that heart-derived collagen induces better contraction and relaxation of human induced pluripotent stem cell-derived EHT (hiPSC-EHT) and that hiPSC-EHT with heart-derived collagen exhibit more mature profiles than those with collagens from other organs. Further, we found that collagen fibril formation and gel stiffness influence the contraction, relaxation, and maturation of hiPSC-EHT, suggesting the importance of collagen types III and type V, which are relatively abundant in the heart. Thus, we demonstrate the effectiveness of organ-specific collagens in tissue engineering and drug discovery.

Development and validation of a collagen signature to predict the prognosis of patients with stage II/III colorectal cancer

The tumor, nodes and metastasis (TNM) classification system provides useful but incomplete prognostic information and lacks the assessment of the tumor microenvironment (TME). Collagen, the main component of the TME extracellular matrix, plays a nonnegligible role in tumor invasion and metastasis. In this cohort study, we aimed to develop and validate a TME collagen signature (CSTME) for prognostic prediction of stage II/III colorectal cancer (CRC) and to compare the prognostic values of "TNM stage+ CSTME" with that of TNM stage alone. Results indicated that the CSTME was an independent prognostic risk factor for stage II/III CRC (hazard ratio: 2.939, 95% CI: 2.180-3.962, p<0.0001), and the integration of the TNM stage and CSTME had a better prognostic value than that of the TNM stage alone (AUC(TNM+CSTME)= 0.772, AUC TNM= 0.687, p<0.0001). This study provided an application of "seed and soil" strategy for prognosis prediction and individualized therapy.

Abstract 3899: CHST11 mediated SEMA7A expression contributes to TKI resistant in lung cancer

Abstract An extracellular matrix has been demonstrated to be one of the substances that promote tumor cells to become driven by external stimuli to change their biology or malignancy. The main component of extracellular matrix, chondroitin sulfate, has been confirmed as a factor in the progression of tumors. Nevertheless, a great deal remains unknown regarding the precise mechanisms that drive Chondroitin sulfate production and how these details are communicated to cancer cells. According to our previous studies, the main enzyme responsible for Chondroitin sulfate synthesis, carbohydrate sulfotransferase 11 (CHST11), plays a crucial role in lung cancer cell metastatic spread. Nevertheless, the relationship between CHST11 expression and regulatory mechanism in response to lung cancer treatment is unclear, especially for tyrosine kinase inhibitor (TKI). A clinical correlation analysis was used in this study to identify molecules which were highly correlated with the overexpression of CHST11 and identified GPI-anchored protein semaphorin 7A (SEMA7A) as a candidate. According to the TCGA database, expression of upregulated SEMA7A is correlated with poor prognosis and cellular malignancy in lung cancer patients. A SEMA7A-based gene correlation analysis finds that the affected gene ontology is highly similar to CHST11, particularly integrin signaling, which may contribute to Gefitinib resistance. A GSEA analysis reveals a significant effect of CHST11 overexpression on mitotic spindle processes, some of which molecules are clinically relevant to CHST11 or SEMA7A. These molecules have been reported to be involved in TKI resistance events such as MARCKS, MYO1E, and PDLIM5. Based on the TCGA database, these molecules and integrins also display significant clinical relevance in lung cancer patients. A CHST11-mediated increase in SEMA7A in the mitotic spindle process of cells may serve as one of the possible means of reducing TKI-induced mitotic cell death, and thereby promoting the ability of lung cancer cells to become resistant to TKIs. Hence, targeting the CHST11-SEMA7A axis may offer a therapeutic strategy option that could be used to target drug resistance in lung cancers. [Keywords: CHST11, SEMA7A, Integrin, Drug resistant, Lung cancer] (Reference: https://pubmed.ncbi.nlm.nih.gov/35985204/; https://pubmed.ncbi.nlm.nih.gov/36181245/) Citation Format: Chien-Hsiu Chris Li, Ming-Hsien Chan, Yu-Chan Chang, Michael Hsiao. CHST11 mediated SEMA7A expression contributes to TKI resistant in lung cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3899.

Abstract 1191: Targeting the tumor extracellular matrix to enhance therapeutic interventions in glioblastoma

Abstract Brain cancers remain some of the most challenging tumors to treat. The goal of our research is to use a 3D in vitro model to acquire in-depth understanding on the unique environment of brain tumors in order to find new biomarkers of disease and develop more efficient therapeutic approaches. Brain extracellular matrix (ECM) plays a key role in glioblastoma invasion and therapeutic resistance. In particular, the aberrant biosynthesis of the main component of brain ECM, hyaluronic acid (HA), has been associated to pathological conditions. In this study, we investigate the influence of tumor extracellular microenvironment in glioblastoma progression. We focus here on the tumor-associated HA biosynthesis in response to biophysical alterations, such as hypoxia and stiffness, and after radio and chemotherapeutic interventions. The ability to manipulate tumor ECM can improve therapeutic outcomes and restrict glioblastoma growth and infiltration. We have established engineered brain tumor biomaterials based on functionalized gelatin hydrogels decorated with covalently bound HA. This biomaterial approach can monitor the response of patient-derived xenograft cell populations with different molecular signatures (1, 2) in combination with microfluidic devices. Here, we characterized tumor cell response to targeted inhibitors and ionizing radiation. We quantified HA molecular weight (MW) distribution of secreted HA, and the tumor cell response to inhibition of HA synthase 2 (HAS2) and hyaluronidase (Hyal). Analysis of HA biosynthesis suggests that GBM cells compensate for a lack of matrix-bound HA by producing soluble HA to stimulate invasion. Moreover, we revealed that different signaling pathways are altered in the tumor cells depending on the microenvironment as they respond to an EGFR and CD44 inhibitor. While the decrease in invasion and proliferation in gelatin-only matrices comes from the negative regulation of ERK pathway, HA plays a favorable role in the inhibition of EGFR, through STAT3 deactivation (3). The MW and abundance of HA are mediated by the activity of HA synthases and hyaluronidases. These enzymes vary in expression, rate, and MW of the HA produced. We have found a heterogeneous profile of MW distributions secreted by different tumor types when exposed to different targeted inhibitors. We have also shown an increase in HA secretion after exposure to radiation and inhibition of hyaluronidase, also associated to significant changes in cell proliferation. The oxidative stress induced by the hypoxic environment also induces the production of hyaluronic acid and significantly affects glycolysis and mitochondrial oxidative phosphorylation, that are further altered by the molecular weight of the HA present in the extracellular space. (1) Pedron S. Adv. Healthcare Mater. 2017; 6:1700529; (2) Pedron S. MRS Commun. 2017; 7:442-449; (3) Pedron S. Biomaterials 2019; 219:119371. Citation Format: Edward R. Neves, Joseph Mueller, Achal Anand, Kimberly A. Selting, Brendan A. Harley, Sara Pedron-Haba. Targeting the tumor extracellular matrix to enhance therapeutic interventions in glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1191.

Biocompatible and bioactive hydrogels of recombinant fusion elastin with low transition temperature for improved healing of UV-irradiated skin.

Prolonged exposure to UV radiation can cause severe photodamage to the skin, leading to abnormal fragmentation of elastin fibers. As one of the main protein components of the dermal extracellular matrix, elastin plays a critical role in the mechanical behavior and physiological function of the skin. Animal-derived elastin has attracted extensive attention in tissue engineering, however it suffers from severe drawbacks such as a risk of virus transmission, ready degradation, and challenging quality control. Herein, we have for the first time developed a novel recombinant fusion elastin (RFE) and its cross-linked hydrogel for improved healing efficacy for UV-irradiated skin. RFE showed temperature-sensitive aggregation behavior similar to natural elastin. Compared with recombinant elastin without the fusion V-foldon domain, RFE showed a much more ordered secondary structure and lower transition temperature. Furthermore, Native-PAGE results indicated that the addition of the V-foldon domain triggered the formation of remarkable oligomers in RFE, which may result in a more ordered conformation. Tetrakis Hydroxymethyl Phosphonium Chloride (THPC) cross-linking of RFE led to the production of a fibrous hydrogel with uniform three-dimensional porous nanostructures and excellent mechanical strength. The RFE hydrogel showed superior cellular activity, significantly promoting the survival and proliferation of human foreskin fibroblast-1 (HFF-1). Studies of mice models of UV-irradiated skin demonstrated that the RFE hydrogel pronouncedly accelerated their healing process by inhibiting epidermal hyperplasia as well as boosting the regeneration of collagen and elastin fibers. The highly biocompatible and bioactive recombinant fusion elastin and its cross-linked hydrogel provide a potent treatment for photodamaged skin, which may have promising applications in dermatology and tissue engineering.

Organic Bone Matrix Component Type I and V Collagen Are Not Destructed in Bisphosphonate-Associated Osteonecrosis of the Jaws.

Background and objectives: The investigation of the pathophysiology behind medication-related osteonecrosis (MRONJ) of the jaw mostly focuses on alterations in osteoclast and osteoblast cell activity, but changes in the organic and inorganic bone matrix have rarely been studied. The aim of this study was to investigate whether collagen, the main organic component of extracellular bone matrix, is destructed in osteonecrosis of the jaw secondary to antiresorptive medication. Material and methods: Bone samples of patients with MRONJ (n = 15, control group n = 3) were demineralized, and collagen fragments were separated from intact collagen pellets by ultrafiltration. The quantification of mature collagen cross-links hydroxylysylpyridinoline (HP) and lysylpyridinoline (LP) in pellets and ultrafiltrates was performed by high-performance liquid chromatography (HPLC). The detection of hydroxyproline (Hyp) was carried out using a spectrophotometric assay. In addition, collagen chains were analyzed by sodium dodecylsulfate-polyacrylamide gel (SDS-PAGE). Results: The results revealed significantly higher concentrations of HP, LP and Hyp in pellet samples. In addition, there were no significant differences between samples from MRONJ patients and those of the control group. These results were paralleled by SDS- PAGE. Conclusion: These findings suggest that MRONJ does not involve the destruction of type I and V collagen molecules, in contrast to previously reported destruction by osteoradionecrosis.

A Reaction of the Mouse Spleen Extracellular Matrix to Administration of Liposome-Encapsulated Dextrazide in Stabilization Period of BCG-Induced Inflammation

The objective: to study a response of the spleen extracellular matrix (ECM) to the liposome-encapsulated dextrazide (LEDZ) administration in the stabilization period of BCG-induced granulomatosis.Subjects and Methods. A model of generalized tuberculosis inflammation was reproduced by injecting mice with mycobacteria from BCG vaccine (BCG-infected mice). Intact mice served as controls. During inflammation stabilization, the infected mice were dosed with LEDZ by inhalation and intraperitoneal injection, and main ECM components were assessed.Results. The BCG-infected mice showed a decrease in the structural components of proteoglycans (PGs) but demonstrated elevated profibrotic fractions of hydroxyproline (Hyp), enhanced activity of matrix metalloproteinases (MMPs) and no differences in the content of their tissue inhibitors (TIMPs), that indicated the fibrosis of the organ. Despite the way of LEDZ administration, the level of uronic acids in PGs and activity of hyaluronidases increased but the content of protein-bound Hyp was reduced with no differences in the content of free Hyp versus infected untreated mice. The administration of LEDZ by inhalation reduced content of profibrotic fractions of Hyp but increased galactose in PGs increased to the level of control mice. The intraperitoneal LEDZ administration decreased the protein content in PGs.

Boswellia serrata Extract, 5-Loxin®, Prevents Joint Pain and Cartilage Degeneration in a Rat Model of Osteoarthritis through Inhibition of Inflammatory Responses and Restoration of Matrix Homeostasis.

Osteoarthritis (OA) is a chronic, progressive joint disease associated with pain, functional impairment, and diminished quality of life in affected individuals. At a societal level, it also has a high economic burden. Boswellia serrata has been reported to have potent anti-inflammatory, antiarthritic, and analgesic effects. The aim of this study was to explore the therapeutic potential and possible underlying mechanism of 5-Loxin®, a standardized Boswellia serrata extract, in a rat model of OA. The OA model was established by the intra-articular injection of 50 μL of monosodium iodoacetate (MIA) (60 mg/mL). 5-Loxin® was administered orally, and efficacy was evaluated through serum analysis, real-time polymerase chain reaction (PCR), histologic staining, and micro-computed tomography (micro-CT). Results indicated that administration of 5-Loxin® can relieve OA joint pain through inhibition of both inflammatory processes and cartilage degeneration. In the group of rats treated with 5-Loxin®, the suppression of inflammatory enzymes such as cyclooxygenase (COX)-2 and 5-lipoxygenase (LOX) resulted in a significant reduction in the prostaglandin (PG) E2 and leukotriene (LT) B4 levels. Moreover, 5-Loxin® ameliorated the deterioration of the main components of the articular extracellular matrix (ECM), such as glycosaminoglycans (GAGs) and aggrecan, through the downregulation of matrix metalloproteinases (MMPs). These findings suggest that 5-Loxin® may be a potential therapeutic agent for the treatment of OA.

Decellularization alters the unfavorable regenerative adverse microenvironment of the injured spinal cord to support neurite outgrowth.

BackgroundAcellular tissue has been transplanted into the injury site as an external microenvironment to intervene with imbalance microenvironment that occurs after spinal cord injury (SCI) and stimulating axonal regeneration, although the mechanism is unclear. Given decellularization is the key means to obtain acellular tissues, we speculated changes in the internal components of tissue caused by decellularization may be the key reason why acellular tissues affect remodeling of the microenvironment.MethodsComplete spinal cord crush in a mouse model was established, and the dynamic of extracellular matrix (ECM) expression and distribution during SCI was studied with immunohistochemistry (IHC). Normal spinal cord (NSC) and 14-day injury spinal cord (ISC) were obtained to prepare the decellularized NSC (DNSC) and decellularized ISC (DISC) through a well-designed decellularization method, and the decellularization effects were evaluated by residual DNA content determination, hematoxylin and eosin staining (H&E), and IHC. Rat dorsal root ganglia (DRG) were co-cultured with NSC, ISC, DNSC, and DISC to evaluate their effect on neurite outgrowth. Furthermore, the mechanisms by which decellularized tissue promotes axonal growth were explored with proteomics analysis of the protein components and function of 14-day ISC and DISC.ResultsWe found the expression of the four main ECM components (collagen type I and IV, fibronectin, and laminin) gradually increased with the progression of SCI compared to NSC, peaking at 14 days of injury then slightly decreasing at 21 days, and the distribution of the four ECM proteins in the ISC also changed dynamically. H&E staining, residual DNA content determination, and IHC showed decellularization removed cellular components and preserved an intact ECM. The results of co-cultured DRG with NSCs, ISCs, DNSCs, and DISCs showed DNSCs and DISCs had a stronger ability in supporting neurite outgrowth than NSC and ISC. We found through proteomics that decellularization could remove proteins associated with inflammatory responses, scarring, and other pathological factors, while completely retaining the ECM proteins.ConclusionsTaken together, our findings demonstrate decellularization can optimize the imbalanced microenvironment after SCI by removing components that inhibit spinal cord regeneration, providing a theoretical basis for clinical application of acellular tissue transplantation to repair SCI.

An Effective Method for Decellularization of Human Foreskin: Implications for Skin Regeneration in Small Wounds.

Objective Acellular matrices of different allogeneic or xenogeneic origins are widely used as structural scaffolds in regenerative medicine. The main goal of this research was to optimize a method for decellularization of foreskin for skin regeneration in small wounds. Materials and Methods In this experimental study, the dermal layers of foreskin were divided into two sections and subjected to two different decellularization methods: the sodium dodecyl sulfate method (SDS-M), and our optimized foreskin decellularization method (OFD-M). A combination of non-ionic detergents and SDS were used to decellularize the foreskin in OFD-M. The histological, morphological, and biomechanical properties of both methods were compared. In addition, human umbilical cord mesenchymal stem cells (hucMSCs) were isolated, and the biocompatibility and recellularization of both scaffolds by hucMSC were subsequently determined. Results We observed that OFD-M is an appropriate approach for successful removal of cellular components from the foreskin tissue, without physical disturbance to the acellular matrix. In comparison to SDS-M, this new bioscaffold possesses a fine network containing a high amount of collagen fibers and glycosaminoglycans (GAG) (P≤0.03), is biocompatible and harmless for hucMSC (viability 91.7%), and exhibits a relatively high tensile strength. ConclusionWe found that the extracellular matrix (ECM) structural integrity, the main ECM components, and the mechanical properties of the foreskin are well maintained after applying the OFD-M decellularization technique, indicating that the resulting scaffold would be a suitable platform for culturing MSC for skin grafting in small wounds.