Heparin-collagen I bilayers stimulate FAK/ERK½ signaling via α2β1 integrin to support the growth and anti-inflammatory potency of mesenchymal stromal cells

Understanding mesenchymal stromal cells (MSCs) growth mechanisms in response to surface chemistries is essential to optimize culture methods for high-quality and robust cell yields in cell manufacturing applications. Heparin (HEP) and collagen 1 (COL) substrates have been reported to enhance cell adhesion, growth, viability, and secretory potential in MSCs. However, the biomolecular mechanisms underlying the benefits of combined HEP/COL substrates are unknown. This work used HEP/COL bilayered surfaces to investigate the role of integrin-HEP interactions in the advantages of MSC culture. The layer-by-layer approach (LbL) was used to create HEP/COL bilayers, which were made up of stacks of 8 and 9 layers that combined HEP and COL in an alternate arrangement. Surface spectroscopic investigations and laser scanning microscopy evaluations verified the biochemical fingerprint of each component and a total stacked bilayer thickness of roughly 150 nm. Cell growth and apoptosis in response to IC50 and IC75 levels of BTT-3033 and Cilengitide, α2β1 and αvβ3 integrin inhibitors respectively, were evaluated on HEP/COL coated surfaces using two bone marrow-derived MSC donors. While integrin activity did not affect cell growth rates, it significantly affected cell adhesion and apoptosis on HEP/COL surfaces. HEP-ending HEP/COL surfaces significantly increased FAK-ERK½ phosphorylation and endogenous cell COL deposition compared to COL, COL-ending HEP/COL and uncoated surfaces. BTT-3033 but not Cilengitide treatment markedly affected FAK-ERK½ activity levels on HEP-ending HEP/COL surfaces supporting a major role for α2β1 activity. BTT-3033 treatment on HEP-ending bilayers reduced MSC-mediated macrophage inhibitory activity and altered the cytokine profile of co-cultures. Overall, this study supports a novel role for HEP in regulating the survival and potency of MSCs via enhancing the α2β1-FAK-ERK½ signaling mechanism.

Implantation of bovine hydroxyapatite and secretome with different oxygen concentration may improve massive bone defect regeneration: An experimental study on animal model

The most widely used biomaterials in the treatment of massive bone defects are allograft bone or metal implants. The current problem is that the availability of allographs is limited and metal implants are very expensive. Mass production of secretome can make bone reconstruction of massive bone defects using a scaffold more effective and efficient. This study aims to prove bone regeneration in massive bone defects using bovine hydroxyapatite reconstruction with normoxic and hypoxic secretome conditions using collagen type 1 (COL1), alkaline phosphate (ALP), osteonectin (ON), and osteopontin (OPN) parameters. This is an in vivo study using male New Zealand white rabbits aged 6-9 months. The research was carried out at the Biomaterials Center-Tissue Bank, Dr. Soetomo Hospital for the manufacturer of bovine hydroxyapatite (BHA) and secretome BM-MSC culture under normoxic and hypoxic conditions, and UNAIR Tropical Disease Institute for implantation in experimental animals. Data analysis was carried out with the one-way ANOVA statistical test and continued with the Post Hoc test LSD statistical test to determine whether or not there were significant differences between groups. There were significant differences between hypoxic to normoxic group and hypoxic to BHA group at day-30 observation using ALP, COL 1, ON, and OPN parameters. Meanwhile, there is only osteonectin parameter has significant difference at day-30 observation. At day-60 observation, only OPN parameter has significant differences between hypoxic to normoxic and hypoxic to BHA group. Between day-30 and day-60 observation, BHA and normoxic groups have a significant difference at all parameters, but in hypoxic group, there are only difference at ALP, COL 1, and ON parameters. Hypoxic condition BM-MSC secretome with BHA composite is superior and could be an option for treating bone defect.

Collagen polarization promotes epithelial elongation by stimulating locoregional cell proliferation

Epithelial networks are commonly generated by processes where multicellular aggregates elongate and branch. Here, we focus on understanding cellular mechanisms for elongation using an organotypic culture system as a model of mammary epithelial anlage. Isotropic cell aggregates broke symmetry and slowly elongated when transplanted into collagen 1 gels. The elongating regions of aggregates displayed enhanced cell proliferation that was necessary for elongation to occur. Strikingly, this locoregional increase in cell proliferation occurred where collagen 1 fibrils reorganized into bundles that were polarized with the elongating aggregates. Applying external stretch as a cell-independent way to reorganize the extracellular matrix, we found that collagen polarization stimulated regional cell proliferation to precipitate symmetry breaking and elongation. This required β1-integrin and ERK signaling. We propose that collagen polarization supports epithelial anlagen elongation by stimulating locoregional cell proliferation. This could provide a long-lasting structural memory of the initial axis that is generated when anlage break symmetry.

Leflunomide Induces Dose-Dependent Lung Injury in Mice via Stimulating Vimentin and NLRP3 Inflammasome Production

Recently, the therapeutic importance of the anti-rheumatic drug, leflunomide, has been increased after the involvement of leflunomide in treating other autoimmune diseases and its promising role in retarding human malignancies. Few studies have focused on the safety in human or animals without clear outlining of the pathologic features on target organs. One clinical study related leflunomide with significant pulmonary complications in predisposed individuals. The current study examined the dose-dependent lung injury produced by leflunomide in healthy mice. Albino mice were allocated into four different groups. Group (1): Vehicle control group, Group (2–4): mice received leflunomide (2.5, 5 or 10 mg/kg), respectively, for 8 weeks and then lungs were dissected from the mice for histopathological examination and fibrosis evaluation (Masson’s trichrome staining and α-smooth muscle actin immunohistochemistry). Enzyme linked immunosorbent assay was used to assess the vimentin and other inflammatory factors in the lung homogenate whereas Western blot analysis was employed to assess α-smooth muscle actin, vimentin and collagen 1. Results indicated that leflunomide induced dose-dependent pulmonary injury and the high dose and increased the vimentin, inflammatory markers (NLRP3 and interlukin-1β). Histologic examination showed distorted architecture, marked inflammatory cells infiltrate and increase collagen content. The findings were supported by Western blotting and the immunohistochemical study which showed greater pulmonary α-smooth muscle actin and vimentin content. In conclusion, the current results highlighted that leflunomide produced dose-dependent pulmonary toxicities that requires further investigation of the nature of injury.

Phenalen-1-one-mediated photodynamic therapy inhibits keloid graft progression by reducing vessel formation and promoting fibroblast apoptosis

BACKGROUND

Keloid is a unique refractory syndrome characterized by a proliferation disorder of the fibroblasts. Recently, photodynamic therapy (PDT) has become a promising technique to modulate fibroblasts. However, use of the photosensitizer Phenalen-1-one (Ph1) in PDT for keloid remains to be explored.

OBJECTIVES

This study investigated the efficacy of Ph1-PDT in the in vitro and in vivo models of keloid.

MATERIAL AND METHODS

Cell viability was assessed with a Cell Counting Kit-8 (CCK-8) analysis in keloid fibroblasts. The migrated and invaded keloid fibroblasts after Ph1-PDT were detected using scratch and matrigel invasion assays in vitro. Flow cytometry measured the apoptosis changes. The protein concentrations and the mRNA expression of inflammatory modulators (interleukin 8 (IL-8) and IL-1β) were determined using enzyme-linked immunosorbent assay (ELISA) and real-time quantitative polymerase chain reaction (RT-qPCR) methods, respectively. Nude mice were used to perform the transplantation of keloid grafts. Western blot analysis measured the protein expression of CD31, CD34, tumor growth factor β1 (TGF-β1), and collagen 1 in keloid fibroblasts and grafts.

RESULTS

Our results revealed that Ph1-PDT significantly suppressed cell viability, migration and invasion, and enhanced the rate of cell apoptosis and caspase-3 expression in keloid fibroblasts. Moreover, in the nude mice model, Ph1-PDT decreased the volume of the graft and attenuated the vessel density by inhibiting the expression of vessel density biomarkers (CD31 and CD34) in keloid grafts. Furthermore, Ph1-PDT significantly inactivated the inflammatory mediators in keloid grafts. In addition, Ph1-PDT considerably attenuated the development of keloids by inhibiting TGF-β1 and collagen 1 proteins in keloid fibroblasts and grafts.

CONCLUSIONS

Ph1-PDT may suppress keloid progression by reducing vessel formation and inflammation, and promoting fibroblast apoptosis, suggesting a potential therapy method for keloid.

Electrospun Icariin-Loaded Core-Shell Collagen, Polycaprolactone, Hydroxyapatite Composite Scaffolds for the Repair of Rabbit Tibia Bone Defects

Background

Electrospinning is a widely used technology that can produce scaffolds with high porosity and surface area for bone regeneration. However, the small pore sizes in electrospun scaffolds constrain cell growth and tissue-ingrowth. In this study, novel drug-loading core-shell scaffolds were fabricated via electrospinning and freeze drying to facilitate the repair of tibia bone defects in rabbit models.

Materials and Methods

The collagen core scaffolds were freeze-dried containing icariin (ICA)-loaded chitosan microspheres. The shell scaffolds were electrospun using collagen, polycaprolactone and hydroxyapatite materials to form CPH composite scaffolds with the ones containing ICA microspheres named CPHI. The core-shell scaffolds were then cross-linked by genipin. The morphology, microstructure, physical and mechanical properties of the scaffolds were assessed. Rat marrow mesenchymal stem cells from the wistar rat were cultured with the scaffolds. The cell adhesion and proliferation were analysed. Adult rabbit models with tibial plateau defects were used to evaluate the performance of these scaffolds in repairing the bone defects over 4 to 12 weeks.

Results

The results reveal that the novel drug-loading core-shell scaffolds were successfully fabricated, which showed good physical and chemical properties and appropriate mechanical properties. Furthermore, excellent cells attachment was observed on the CPHI scaffolds. The results from radiography, micro-computed tomography, histological and immunohistochemical analysis demonstrated that abundant new bones were formed on the CPHI scaffolds.

Conclusion

These new core-shell composite scaffolds have great potential for bone tissue engineering applications and may lead to effective bone regeneration and repair.

Biological responses of dental pulp cells to surfaces modified by collagen 1 and fibronectin

Collagen 1 (COL1) and fibronectin (FN) are extracellular matrix proteins that contribute in cell activity and involve in regulating dental pulp cells (DPCs). The purpose of this study was to investigate the effect of COL1 and FN on the behavior of DPCs. Here, DPCs were grown under three different conditions: COL1 coating, FN coating, and control group without coating. The proliferation and differentiation of DPCs were investigated. DPCs in osteogenic media were able to differentiate into osteoblastic phenotype. The morphological analysis revealed no obvious difference on the shape of cells. Cells had spread well on both coated and noncoated culture plates with slightly more spreading in the coated plates after 24 hr. The MTT analysis did not demonstrate a significant difference at 1 and 3 hr among the groups, but interestingly, the analysis disclosed more cells on the coated plates after longer cultures, which indicated a higher proliferative capacity in response to COL1 and FN. RT-PCR, Western Blotting and mineralization assays did not reveal significant differences between the coated and noncoated surfaces in relation to osteogenic differential potential. Our data suggested that the surface coating of COL1 and FN were able to promote cellular proliferation and the osteogenic differentiation tendency of DPCs was also observed in vitro.

Osteopontin and phospho-SMAD2/3 are associated with calcification of vessels in D-CAA, an hereditary cerebral amyloid angiopathy

In severe forms of cerebral amyloid angiopathy (CAA) pathology, vascular calcification has been observed in the cerebral cortex, both in vivo on MRI and CT, and post-mortem using histopathology. However, the pathomechanisms leading to calcification of CAA-laden arteries are unknown. Therefore, we investigated the correlation between calcification of cortical arterioles and several potential modulators of vascular calcification using immunohistochemistry in a unique collection of brain material of patients with a hereditary form of CAA, namely hereditary cerebral hemorrhage with amyloidosis-Dutch type (HCHWA-D or D-CAA). We show a topographical association of osteopontin (OPN) and TGFβ signaling factor phospho-SMAD2/3 (pSMAD2/3) in calcified CAA vessel walls. OPN and pSMAD2/3 gradually accumulate in vessels prior to calcification. Moreover, we found that the vascular accumulation of Collagen 1 (Col1), OPN and pSMAD2/3 immunomarkers correlated with the CAA severity. This was independently of the vessel size, including capillaries in the most severe cases. We propose that calcification of CAA vessels in the observed HCHWA-D cases may be induced by extracellular OPN trapped in the fibrotic Col1 vessel wall, independently of the presence of vascular amyloid.

Effects of mangosteen peel extract combined with demineralized freeze-dried bovine bone xenograft on osteocalcin, collagen 1, and osteoblast as alveolar bone regeneration in socket preservation

Background:

Tooth extraction will provoke changes in alveolar bone morphology and dimensions. Postextraction bone resorption can lead to significant problems for restorative dentistry. Therefore, the extracted tooth socket needs to be preserved to reduce alveolar ridge bone resorption. This research aimed to analyze the expression and levels of osteocalcin, collagen 1, and osteoblasts in extracted tooth sockets filled with a combination of mangosteen peel extract and demineralized freeze-dried bovine bone xenograft (DFDBBX).

Material and Methods:

Fifty-six Cavia cobaya, whose lower left incisors had been extracted, were divided into eight groups according to the substance used to fill their sockets on days 7 and 30, Poly ethylene glycol, DFDBBX, mangosteen peel extract, or a combination of mangosteen peel extract and DFDBBX. This research was conducted in several stages; the application of mangosteen peel extract combined with graft material was performed as the form of tooth extraction socket preservation. The C. cobaya rats were subsequently examined by immunohistochemical methods to measure osteocalcin and collagen 1 expressions, whereas histological examination was conducted to calculate the number of osteoblasts in accordance with the duration of the research.

Results:

On days 7 and 30, the group treated with a combination of DFDBBX and mangosteen peel extract which had the highest expression and levels of osteocalcin, collagen 1, and osteoblasts.

Conclusion:

The administration of mangosteen peel extract combined with DFDBBX as a means of tooth extraction socket preservation can increase osteocalcin and collagen 1 expression. Consequently, osteoblasts as a means of alveolar bone regeneration will increase in number.

MicroRNA29a Treatment Improves Early Tendon Injury

Tendon injuries (tendinopathies) are common in human and equine athletes and characterized by dysregulated collagen matrix, resulting in tendon damage. We have previously demonstrated a functional role for microRNA29a (miR29a) as a post-transcriptional regulator of collagen 3 expression in murine and human tendon injury. Given the translational potential, we designed a randomized, blinded trial to evaluate the potential of a miR29a replacement therapy as a therapeutic option to treat tendinopathy in an equine model that closely mimics human disease. Tendon injury was induced in the superficial digital flexor tendon (SDFT) of 17 horses. Tendon lesions were treated 1 week later with an intralesional injection of miR29a or placebo. miR29a treatment reduced collagen 3 transcript levels at week 2, with no significant changes in collagen 1. The relative lesion cross-sectional area was significantly lower in miR29a tendons compared to control tendons. Histology scores were significantly better for miR29a-treated tendons compared to control tendons. These data support the mechanism of microRNA-mediated modulation of early pathophysiologic events that facilitate tissue remodeling in the tendon after injury and provides a strong proof of principle that a locally delivered miR29a therapy improves early tendon healing.

Physiological loading of tendons induces scleraxis expression in epitenon fibroblasts

Scleraxis is a basic helix-loop-helix transcription factor that plays a central role in promoting fibroblast proliferation and matrix synthesis during the embryonic development of tendons. Mice with a targeted inactivation of scleraxis (Scx(-/-)) fail to properly form limb tendons, but the role that scleraxis has in regulating the growth and adaptation of tendons of adult organisms is unknown. To determine if scleraxis expression changes in response to a physiological growth stimulus to tendons, we subjected adult mice that express green fluorescent protein (GFP) under the control of the scleraxis promoter (ScxGFP) to a 6-week-treadmill training program designed to induce adaptive growth in Achilles tendons. Age matched sedentary ScxGFP mice were used as controls. Scleraxis expression was sparsely observed in the epitenon region of sedentary mice, but in response to treadmill training, scleraxis was robustly expressed in fibroblasts that appeared to be emerging from the epitenon and migrating into the superficial regions of tendon fascicles. Treadmill training also led to an increase in scleraxis, tenomodulin, and type I collagen gene expression as measured by qPCR. These results suggest that in addition to regulating the embryonic formation of limb tendons, scleraxis also appears to play an important role in the adaptation of adult tendons to physiological loading.

Chondrocyte source for cartilage regeneration in an immature animal: Is iliac apophysis a good alternative?

BACKGROUND

Autologous articular cartilage at present forms the main source of chondrocytes for cartilage tissue engineering. In children, iliac apophysis is a rich and readily accessible source of chondrocytes. This study compares the growth characteristics and phenotype maintenance of goat iliac apophysis growth plate chondrocytes with those sourced from goat articular cartilage, and thereby assesses their suitability for autologous chondrocyte transplantation in immature animals for growth plate and articular cartilage regeneration.

MATERIALS AND METHODS

Four sets of experiments were carried out. Cartilage samples were harvested under aseptic conditions from goat iliac apophysis and knee articular cartilage. The chondrocytes were isolated in each set and viable cells were counted and subsequently cultured as a monolayer in tissue culture flasks containing chondrogenic media at 2.5 × 10(3)cells/cm(2). The growth was periodically assessed with phase contrast microcopy and the cells were harvested on 8(th) and 15(th) days for morphology, cell yield, and phenotype assessment. Student's t-test was used for comparison of the means.

RESULTS

Confluence was reached in the iliac apophysis growth plate chondrocytes flasks on the 10(th) day and the articular cartilage chondrocytes flasks on the 14(th) day. Mean cell count of growth plate chondrocytes on the 8(th) day was 3.64 × 10(5) (SD = 0.601) and that of articular cartilage chondrocytes was 1.40 × 10(5) (SD = 0.758) per flask. The difference in the means was statistically significant (P = 0.003). On the 15(th) day, the mean cell number had increased to 1.35 × 10(6)(SD = 0.20) and 1.19 × 10(6) (SD = 0.064) per flask, respectively. This difference was not statistically significant (P = 0.26). The population doubling time on the 8(th) day of cell culture was 3.18 and 6.24 days respectively, for iliac apophyseal and articular cartilage chondrocytes, which was altered to 3.59 and 3.1 days, respectively, on the 15(th) day. The immunocytochemistry showed 100% retention of collagen 2 positive and collagen 1 negative cells in both sets of cultures in all samples.

CONCLUSION

Iliac apophysis is a rich source of chondrocytes with a high growth rate and ability to retain phenotype when compared to articular cartilage derived chondrocytes. Further in vivo studies may determine the efficacy of physeal and articular repair in children with apophyseal chondrocytes.