Proliferation Of Mesenchymal Stem Cells Research Articles

Hydrogen Sulfide Delivery to Enhance Bone Tissue Engineering Cell Survival.

Though crucial for natural bone healing, local calcium ion (Ca2+) and phosphate ion (Pi) concentrations can exceed the cytotoxic limit leading to mitochondrial overload, oxidative stress, and cell death. For bone tissue engineering applications, H2S can be employed as a cytoprotective molecule to enhance mesenchymal stem cell (MSC) tolerance to cytotoxic Ca2+/Pi concentrations. Varied concentrations of sodium hydrogen sulfide (NaSH), a fast-releasing H2S donor, were applied to assess the influence of H2S on MSC proliferation. The results suggested a toxicity limit of 4 mM for NaSH and that 1 mM of NaSH could improve cell proliferation and differentiation in the presence of cytotoxic levels of Ca2+ (32 mM) and/or Pi (16 mM). To controllably deliver H2S over time, a novel donor molecule (thioglutamic acid-GluSH) was synthesized and evaluated for its H2S release profile. Excitingly, GluSH successfully maintained cytoprotective level of H2S over 7 days. Furthermore, MSCs exposed to cytotoxic Ca2+/Pi concentrations in the presence of GluSH were able to thrive and differentiate into osteoblasts. These findings suggest that the incorporation of a sustained H2S donor such as GluSH into CaP-based bone graft substitutes can facilitate considerable cytoprotection, making it an attractive option for complex bone regenerative engineering applications.

The bidirectional effects of APPswe on the osteogenic differentiation of MSCs in bone homeostasis by regulating Notch signaling

Amyloid precursor protein (APP), especially Swedish mutant APP (APPswe), is recognized as a significant pathogenic protein in Alzheimer's disease, but limited research has been conducted on the correlation between APPswe and the osteogenic differentiation of mesenchymal stem cells (MSCs). The effects of APPswe and its intracellular and extracellular segments on the osteogenic differentiation of bone morphogenetic protein 2 (BMP2)-induced MSCs were analyzed in this study. Our analysis of an existing database revealed that APP was positively correlated with the osteogenic differentiation of MSCs but negatively correlated with their proliferation and migration. Furthermore, APPswe promoted BMP2-induced osteogenic differentiation of MSCs, while APPswe-C (APPswe without an intracellular segment) had the opposite effect; thus, the intracellular domain of APPswe may be a key factor in promoting the osteogenic differentiation of MSCs. Additionally, both APPswe and APPswe-C inhibited the proliferation and migration of MSCs. Furthermore, the intracellular domain of APPswe inhibited the activity of the Notch pathway by regulating the expression of the Notch intracellular domain to promote the osteogenic differentiation of MSCs. Finally, APPswe-treated primary rat bone marrow MSCs exhibited the most favorable bone repair effect when a GelMA hydrogel loaded with BMP2 was used for in vivo experiments, while APPswe-C had the opposite effect. These findings demonstrate that APPswe promotes the osteogenic differentiation of MSCs by regulating the Notch pathway, but its extracellular segment blocks the self-renewal, proliferation, and migration of MSCs, ultimately leading to a gradual decrease in the storage capacity of MSCs and affecting long-term bone formation.

A moldable hydrogel based on sericin and Zn2+/F- dual-doped hydroxyapatite promotes skull defect repair through the synergistic effects of immunoregulation, enhanced angiogenesis and osteogenesis

Skull defect repair typically involves multiple stages, including immunomodulation, angiogenesis, osteogenic differentiation, and biomineralization, etc. Most existing therapeutic biomaterials fail to show functional effects across all these stages, leading to unsatisfactory repair effects. To address this challenge, an organic–inorganic hybrid HT(SA)HAp moldable hydrogel with the aforementioned functional properties was developed. The moldable hydrogel consisted of phenylboronic acid-grafted hyaluronic acid, tannic acid, alendronate sodium-grafted sericin (Ser-AL), and hydroxyapatite co-doped with 5 % Zn and 10 % F (Zn5%/F10%-HAp). These materials were cross-linked due to phenylborate ester bonds, metal-phenol interactions, and the AL-mediated chelation of divalent metal cations. Sericin-mediated immunomodulation serves as a precursor to micro-environmental regulation, reducing inflammation at the site of injury and creating an environment conducive to angiogenesis and osteogenic differentiation. The degradation products of the hydrogel’s organic skeleton promoted the proliferation of mesenchymal stem cells and vascular endothelial cells. The enhanced paracrine effect of mesenchymal stem cells and the release of Zn2+ from modified Zn5%/F10%-HAp promoted angiogenesis, while the degradation products of these materials ensured continued promotion of osteogenic differentiation and biomineralization. This organic–inorganic hybrid hydrogel had the synergistic effects of immunoregulation, enhanced angiogenesis, osteogenic differentiation, and biomineralization, which could significantly accelerate the repair of skull defects, and demonstrate completely repaired skull defects at 8 weeks. Thus, this multifunctional moldable hydrogel provided an effective and stable treatment strategy for the rapid repair of skull defects.

A one-step polyphenol-based functionalization strategy of dual-enhanced antibacterial and osteogenic surfaces

Infected bone defect is a critical problem in clinical practice of orthopedics. To solve this problem, implants with dual-functional surfaces which possess both antibacterial and osteogenic properties have extensive applications. However, there remains a pressing need to develop a convenient strategy for preparing such surfaces facilely. In this study, we reported a novel one-step polyphenol-based surface functionalization strategy for preparing two fibrous membranes with antibacterial and osteogenic capabilities. The formation of RGD-HHC36 (RH) or RGD-polyhexamethylene guanidine (RP) coating was fabricated by Michael reaction with poly (tannic acid) (PTA) to produce dual-functional fibrous membranes (PLA-RH and PLA-RP, respectively). The surfaces of PLA-RH and PLA-RP exhibited increased roughness and hydrophilicity. In vitro tests revealed that PLA-RH and PLA-RP could eradicate over 99% of clinically common pathogenic bacteria while exhibiting significant improvements in the adhesion, proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). Moreover, RNA-Seq analysis revealed that the up-regulation of Chrdl1 played a key role in promoting ossification through activation of the CHRDL1-BMP4 pathway. The favourable in vivo anti-infection and osteogenesis-promoting performances were demonstrated in an infected bone defect model. PLA-RH and PLA-RP inhibited bacterial infection in the early stage, and enhanced osteogenesis in the late stage. This study provides a facile and universal strategy for designing and fabricating dual-functional surfaces for antibacterial application and tissue regeneration simultaneously.

Strontium/Silicon/Calcium-Releasing Hierarchically Structured 3D-Printed Scaffolds Accelerate Osteochondral Defect Repair.

Articular cartilage defects are a global challenge, causing substantial disability. Repairing large defects is problematic, often exceeding cartilage's self-healing capacity and damaging bone structures. To tackle this problem, a scaffold-mediated therapeutic ion delivery system is developed. These scaffolds are constructed from poly(ε-caprolactone) and strontium (Sr)-doped bioactive nanoglasses (SrBGn), creating a unique hierarchical structure featuring macropores from 3D printing, micropores, and nanotopologies due to SrBGn integration. The SrBGn-embedded scaffolds (SrBGn-µCh) release Sr, silicon (Si), and calcium (Ca) ions, which improve chondrocyte activation, adhesion, proliferation, and maturation-related gene expression. This multiple ion delivery significantly affects metabolic activity and maturation of chondrocytes. Importantly, Sr ions may play a role in chondrocyte regulation through the Notch signaling pathway. Notably, the scaffold's structure and topological cues expedite the recruitment, adhesion, spreading, and proliferation of chondrocytes and bone marrow-derived mesenchymal stem cells. Si and Ca ions accelerate osteogenic differentiation and blood vessel formation, while Sr ions enhance the polarization of M2 macrophages. The findings show that SrBGn-µCh scaffolds accelerate osteochondral defect repair by delivering multiple ions and providing structural/topological cues, ultimately supporting host cell functions and defect healing. This scaffold holds great promise for osteochondral repair applications.

Comparing the effect of using 2-Mercaptoethanol in the cell culture medium of different cell passages of human mesenchymal stem cells.

Preparing a suitable cell culture medium that supports the biological needs of the growing cells is crucial to enhancing the success rate of any in vitro and in vivo experiments and minimizing undesirable interferences. Mesenchymal stem cells ( MSCs) which are powerful regenerative stem cells require being grown in proper culture media to preserve their stemness and therapeutic properties. MSCs are usually grown in Dulbecco's Modified Eagle low glucose Medium (DMEM low glucose) which contains 5.6 mmol/L of glucose and is supplemented with Fetal Bovine Serum (FBS), antibiotics, and 2-Mercaptoethanol. The addition of 2-Mercaptoethanol to the cell culture medium was proposed long ago and has continued to be used until now. Despite the positive effects of adding 2-Mercaptoethanol in the cell culture medium, its use is still controversial and needs continuous updates to limit its interference with experimental treatments. Herein, we found that 2-Mercaptoethanol is beneficial to enhancing the proliferation and survival of MSCs at higher passage numbers while its effect is negligible for earlier passages. This concise study provides updates regarding the suitable time to add 2-Mercaptoethanol which can minimize its intermeddling with the experimental design and treatments.

Comparative study on physicochemical properties of macroporous hydroxyapatite coatings on 316L stainless steel implants using sol-gel and inverse opal templating

This study focuses on enhancing metallic implant biocompatibility by fabricating a three-dimensional ordered macroporous hydroxyapatite (HAP) architecture through inverse opal technology. Utilizing colloidal crystal templates on 316L stainless steel, specifically with polystyrene and polymethyl methacrylate, successful fabrication was achieved through H2O2 plus H2SO4 etching. The calcination process at different temperatures (350, 500 and 700°C) resulted in distinct HAP structures, and the sample was calcined at 500°C (HAP500), exhibiting superior physicochemical properties, including enhanced crystallinity, surface roughness and wettability. Biological experiments demonstrated that HAP500 significantly promoted mesenchymal stem cell adhesion and proliferation compared to HAP350 and bare 316LSS, suggesting its potential as a highly effective medical device for bone implantation.

An Isotonic Drink Containing Pacific Cod (Gadus macrocephalus) Processing Waste Collagen Hydrolysate for Bone and Cartilage Health.

Malnutrition is one of the major factors of bone and cartilage disorders. Pacific cod (Gadus macrocephalus) processing waste is a cheap and highly promising source of bioactive substances, including collagen-derived peptides and amino acids, for bone and cartilage structure stabilization. The addition of these substances to a functional drink is one of the ways to achieve their fast intestinal absorption. Collagen hydrolysate was obtained via enzymatic hydrolysis, ultrafiltration, freeze-drying, and grinding to powder. The lyophilized hydrolysate was a light gray powder with high protein content (>90%), including collagen (about 85% of total protein) and a complete set of essential and non-essential amino acids. The hydrolysate had no observed adverse effect on human mesenchymal stem cell morphology, viability, or proliferation. The hydrolysate was applicable as a protein food supply or a structure-forming food component due to the presence of collagen fiber fragments. An isotonic fitness drink (osmolality 298.1 ± 2.1 mOsm/L) containing hydrolysate and vitamin C as a cofactor in collagen biosynthesis was prepared. The addition of the hydrolysate did not adversely affect its organoleptic parameters. The production of such functional foods and drinks is one of the beneficial ways of fish processing waste utilization.

Transcriptomics Demonstrates Significant Biological Effect of Growing Stem Cells on RGD-Cotton Scaffold.

Stem cell therapy provides a viable alternative treatment for degenerated or damaged tissue. Stem cells have been used either alone or in conjunction with an artificial scaffold. The latter provides a structural advantage by enabling the cells to thrive in three-dimensional (3D) settings, closely resembling the natural invivo environments. Previously, we disclosed the development of a 3D scaffold made from cotton, which was conjugated with arginyl-glycyl-aspartic acid (RGD), to facilitate the growth and proliferation of mesenchymal stem cells (MSCs). This scaffold allowed the MSCs to adhere and proliferate without compromising their viability or their stem cell markers. A comprehensive analysis investigation of the molecular changes occurring in MSCs adhering to the cotton fibers will contribute to the advancement of therapy. The objective of this study is to analyze the molecular processes occurring in the growth of MSCs on a cotton-RGD conjugated-based scaffold by examining their gene expression profiles. To achieve this, we conducted an experiment where MSCs were seeded with and without the scaffold for a duration of 48 h. Subsequently, cells were collected for RNA extraction, cDNA synthesis, and whole-transcriptomic analysis performed on both populations. Our analysis revealed several upregulated and downregulated differently expressed genes in the MSCs adhering to the scaffold compared with the control cells. Through gene ontology analysis, we were able to identify enriched biological processes, molecular functions, pathways, and protein-protein interactions in these differentially expressed genes. Our data suggest that the scaffold may have the potential to enhance osteogenesis in the MSCs. Furthermore, our results indicate that the scaffold does not induce oxidative stress, inflammation, or aging in the MSCs. These findings provide valuable insights for the application of MSCs in tissue engineering and regenerative medicine.

Tobacco toxins trigger bone marrow mesenchymal stem cells aging by inhibiting mitophagy

Smoking disrupts bone homeostasis and serves as an independent risk factor for the development and progression of osteoporosis. Tobacco toxins inhibit the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs), promote BMSCs aging and exhaustion, but the specific mechanisms are not yet fully understood. Herein, we successfully established a smoking-related osteoporosis (SROP) model in rats and mice through intraperitoneal injection of cigarette smoke extract (CSE), which significantly reduced bone density and induced aging and inhibited osteogenic differentiation of BMSCs both in vivo and in vitro. Bioinformatics analysis and in vitro experiments confirmed that CSE disrupts mitochondrial homeostasis through oxidative stress and inhibition of mitophagy. Furthermore, we discovered that CSE induced BMSCs aging by upregulating phosphorylated AKT, which in turn inhibited the expression of FOXO3a and the Pink1/Parkin pathway, leading to the suppression of mitophagy and the accumulation of damaged mitochondria. MitoQ, a mitochondrial-targeted antioxidant and mitophagy agonist, was effective in reducing CSE-induced mitochondrial oxidative stress, promoting mitophagy, significantly downregulating the expression of aging markers in BMSCs, restoring osteogenic differentiation, and alleviating bone loss and autophagy levels in CSE-exposed mice. In summary, our results suggest that BMSCs aging caused by the inhibition of mitophagy through the AKT/FOXO3a/Pink1/Parkin axis is a key mechanism in smoking-related osteoporosis.

Strategically Designed Bifunctional Polydopamine Enwrapping Polycaprolactone-Hydroxyapatite-Doxorubicin Composite Nanofibers for Osteosarcoma Treatment and Bone Regeneration.

This study presents a new multifunctional nanofibrous drug delivery system to provide effective combination therapy with enormous potential for the treatment of osteosarcoma. We developed a composite nanofiber scaffold comprising poly(ε-caprolactone) (PCL) and hydroxyapatite (HAp)-loaded doxorubicin (DOX) coated with polydopamine (PDA) to combine cancer cell inhibition with bone tissue regeneration. DOX was conjugated with HAp and then mixed with a PCL solution to prepare a PCL/HAp-DOX (labeled PCLDH) nanofiber. Then, in situ polymerization of PDA on the PCLDH occurred to produce the PCLDH@PDA composite nanofiber. The morphology, XRD, FT-IR, wettability, photothermal characteristics, cumulative drug release, and in vitro bioactivities were evaluated. We found that the PDA coating not only enhanced the hydrophilic properties but also controlled drug release. The PCLDH@PDA composite scaffold significantly suppressed the proliferation of bone cancer cells initially and, consequently, improved the adhesion and proliferation of human mesenchymal stem cells (hMSCs). The PDA coating boosted the composite scaffold's bioactivity, as demonstrated through ALP activity, ARS assay, and biomineralization results. This strategy offers a promising dual-function scaffold to treat residual cancer and reconstruct defects after osteosarcoma surgery.

Osteogenerative and corrosion-decelerating teriparatide-mediated strontium–zinc phosphate hybrid coating on biodegradable zinc–copper alloy for orthopaedic applications

Zinc–copper (ZnCu) alloys recently showed great potential as biodegradable materials for bone implants thanks to their excellent mechanical strength, biosafety, and promising bioactivities. However, bare ZnCu alloys exhibited poor cytocompatibility and osteointegration. Moreover, the biological functions of ZnCu remain to be corroborated. Herein, the teriparatide (PTH)-mediated strontium–zinc phosphate (SrZnP) organic–inorganic hybrid coating was fabricated on the surface of ZnCu substrate via a chemical conversion method to contain the release of Zn ions and improve biofunctionality in osteogenesis. The characteristics of the hybrid coating were optimised by adjusting the amount of PTH molecules added. A dense and homogenous coating with micellar crystal micro-/nano-structure was obtained. The coated samples showed a significantly decreased corrosion rate and a more uniform corrosion mode, effectively suppressing the release of Zn2+. Additionally, the coated ZnCu enhanced the proliferation of bone marrow mesenchymal stem cells (BMSCs), promoted the expression of alkaline phosphatase and the formation of calcium nodules, and upregulated the levels of osteogenic-related genes. More important, the hybrid coating activated the classic osteogenic signalling pathway of BMP-2/Smad1/Runx2 and Sirt1/Runx2 to induce the osteogenic differentiation of BMSCs. These appealing features can be mainly attributed to the constituents of released Zn2+, Sr2+, and PTH molecules in the control, as well as the unique topographical characteristics of the coatings. Taken together, the PTH&SrZnP hybrid coating could be a promising option for surface modification of biodegradable metallic Zn for orthopaedic applications.

The allostery and modification of hGHRH molecules and specific dimer produced significant fertility effect by proliferating and activating in-situ ovarian mesenchymal stem cells

The negative coordination of growth hormone secretagogue receptor (GHS-R) and growth hormone-releasing hormone receptor (GHRH-R) involves in the repair processes of cellular injury. The allosteric U- or H-like modified GHRH dimer Grinodin and 2Y were comparatively evaluated in normal Kunming mice and hamster infertility models induced by CPA treatment. 1–3–9 µg of Grinodin or 2Y per hamster stem-cell-exhaustion model was subcutaneously administered once a week, respectively inducing 75–69–46 or 45–13–50 % of birth rates. In comparison, the similar mole of human menopausal gonadotropin (hMG) or human growth hormone (hGH) was administered once a day but caused just 25 or 20 % of birth rates. Grinodin induced more big ovarian follicles and corpora lutea than 2Y, hMG, hGH. The hMG-treated group was observed many distorted interstitial cells and more connective tissues and the hGH-treated group had few ovarian follicles. 2Y had a plasma lifetime of 21 days and higher GH release in mice, inducing lower birth rate and stronger individual specificity in reproduction as well as only promoting the proliferation of mesenchymal-stem-cells (MSCs) in the models. In comparison, Grinodin had a plasma lifetime of 30 days and much lower GH release in mice. It significantly promoted the proliferation and activation of ovarian MSCs together with the development of follicles in the models by increasing Ki67 and GHS-R expressions, and decreasing GHRH-R expression in a dose-dependent manner. However, the high GH and excessive estrogen levels in the models showed a dose-dependent reduction in fertility. Therefore, unlike 2Y, the low dose of Grinodin specifically shows low GHS-R and high GHRH-R expressions thus evades GH and estrogen release and improves functions of organs, resulting in an increase of fertility.

Architecture of β-lactoglobulin coating modulates bioinspired alginate dialdehyde-gelatine/polydopamine scaffolds for subchondral bone regeneration

In this study, we developed polydopamine (PDA)-functionalized alginate dialdehyde-gelatine (ADA-GEL) scaffolds for subchondral bone regeneration. These polymeric scaffolds were then coated with β-Lactoglobulin (β-LG) at concentrations of 1 mg/ml and 2 mg/ml. Morphological analysis indicated a homogeneous coating of the β-LG layer on the surface of network-like scaffolds. The β-LG-coated scaffolds exhibited improved swelling capacity as a function of the β-LG concentration. Compared to ADA-GEL/PDA scaffolds, the β-LG-coated scaffolds demonstrated delayed degradation and enhanced biomineralization. Here, a lower concentration of β-LG showed long-lasting stability and superior biomimetic hydroxyapatite mineralization. According to the theoretical findings, the single-state, representing the low concentration of β-LG, exhibited a homogeneous distribution on the surface of the PDA, while the dimer-state (high concentration) displayed a high likelihood of uncontrolled interactions. β-LG-coated ADA-GEL/PDA scaffolds with a lower concentration of β-LG provided a biocompatible substrate that supported adhesion, proliferation, and alkaline phosphatase (ALP) secretion of sheep bone marrow mesenchymal stem cells, as well as increased expression of osteopontin (SPP1) and collagen type 1 (COL1A1) in human osteoblasts. These findings indicate the potential of protein-coated scaffolds for subchondral bone tissue regeneration. Statement of SignificanceThis study addresses a crucial aspect of osteochondral defect repair, emphasizing the pivotal role of subchondral bone regeneration. The development of polydopamine-functionalized alginate dialdehyde-gelatine (ADA-GEL) scaffolds, coated with β-Lactoglobulin (β-LG), represents a novel approach to potentially enhance subchondral bone repair. β-LG, a milk protein rich in essential amino acids and bioactive peptides, is investigated for its potential to promote subchondral bone regeneration. This research explores computationally and experimentally the influence of protein concentration on the ordered or irregular deposition, unravelling the interplay between coating structure, scaffold properties, and in-vitro performance. This work contributes to advancing ordered protein coating strategies for subchondral bone regeneration, providing a biocompatible solution with potential implications for supporting subsequent cartilage repair.

Highly biologically functional magnesium silicate-coated 3D printed round pore-shaped titanium scaffold alters exosomal miRNA expression to promote osteogenic differentiation for bone defect repair

Bone defects are a serious condition that has a significant impact on the function and quality of life of the patient. In severe bone defects, restoring the structure and function of bone tissue is a complex task, and titanium (Ti) implants designed with superior performance can be an alternative. In this study, in order to develop a Ti implant that effectively promotes osseointegration and new bone ingrowth, 3D printing-based magnesium silicate (MgSiO3)-coated round pore-shaped Ti scaffold (S-R/MgSi) was fabricated by standardizing pore size and porosity and designing different pore shapes and selecting the optimal pore shape (round) as well as subsequent hydrothermal synthesis to finally form MgSiO3 coating. The experimental results of Ti scaffolds with different pore shapes showed that S-R is optimal for promoting osteogenic differentiation. After S-R was coated with MgSiO3, S-R/MgSi enhanced the adhesion, proliferation, migration, and osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs), as well as regulated angiogenesis. In vivo studies, S-R/MgSi significantly promoted new bone ingrowth and was effective in repairing bone defects. Following the mechanism exploration, it was found that exosomes secreted by BMSCs co-cultured with S-R/MgSi (Exo_S-R/MgSi) were more able to promote the osteogenic differentiation of BMSCs. In conclusion, this study not only successfully prepared a new type of Ti implant with superior ability to promote new bone ingrowth, but also provided a new explanation for the mechanism of scaffold surface chemistry affecting osteogenesis from the viewpoint of scaffold surface coating affecting the amount and function of cellular exosome secretion.

Exosomes derived from M2 macrophages prevent steroid-induced osteonecrosis of the femoral head by modulating inflammation, promoting bone formation and inhibiting bone resorption

Inflammatory reactions are involved in the development of steroid-induced osteonecrosis of the femoral head(ONFH). Studies have explored the therapeutic efficacy of inhibiting inflammatory reactions in steroid-induced ONFH and revealed that inhibiting inflammation may be a new strategy for preventing the development of steroid-induced ONFH. Exosomes derived from M2 macrophages(M2-Exos) display anti-inflammatory properties. This study aimed to examine the preventive effect of M2-Exos on early-stage steroid-induced ONFH and explore the underlying mechanisms involved. In vitro, we explored the effect of M2-Exos on the proliferation and osteogenic differentiation of bone marrow-derived mesenchymal stem cells(BMMSCs). In vivo, we investigated the role of M2-Exos on inflammation, osteoclastogenesis, osteogenesis and angiogenesis in an early-stage rat model of steroid-induced ONFH. We found that M2-Exos promoted the proliferation and osteogenic differentiation of BMMSCs. Additionally, M2-Exos effectively attenuated the osteonecrotic changes, inhibited the expression of proinflammatory mediators, promoted osteogenesis and angiogenesis, reduced osteoclastogenesis, and regulated the polarization of M1/M2 macrophages in steroid-induced ONFH. Taken together, our data suggest that M2-Exos are effective at preventing steroid-induced ONFH. These findings may be helpful for providing a potential strategy to prevent the development of steroid-induced ONFH.

Icariin accelerates bone regeneration by inducing osteogenesis-angiogenesis coupling in rats with type 1 diabetes mellitus

BACKGROUND Icariin (ICA), a natural flavonoid compound monomer, has multiple pharmacological activities. However, its effect on bone defect in the context of type 1 diabetes mellitus (T1DM) has not yet been examined. AIM To explore the role and potential mechanism of ICA on bone defect in the context of T1DM. METHODS The effects of ICA on osteogenesis and angiogenesis were evaluated by alkaline phosphatase staining, alizarin red S staining, quantitative real-time polymerase chain reaction, Western blot, and immunofluorescence. Angiogenesis-related assays were conducted to investigate the relationship between osteogenesis and angiogenesis. A bone defect model was established in T1DM rats. The model rats were then treated with ICA or placebo and micron-scale computed tomography, histomorphometry, histology, and sequential fluorescent labeling were used to evaluate the effect of ICA on bone formation in the defect area. RESULTS ICA promoted bone marrow mesenchymal stem cell (BMSC) proliferation and osteogenic differentiation. The ICA treated-BMSCs showed higher expression levels of osteogenesis-related markers (alkaline phosphatase and osteocalcin) and angiogenesis-related markers (vascular endothelial growth factor A and platelet endothelial cell adhesion molecule 1) compared to the untreated group. ICA was also found to induce osteogenesis-angiogenesis coupling of BMSCs. In the bone defect model T1DM rats, ICA facilitated bone formation and CD31hiEMCNhi type H-positive capillary formation. Lastly, ICA effectively accelerated the rate of bone formation in the defect area. CONCLUSION ICA was able to accelerate bone regeneration in a T1DM rat model by inducing osteogenesis-angiogenesis coupling of BMSCs.

HWJMSC-EVs promote cartilage regeneration and repair via the ITGB1/TGF-β/Smad2/3 axis mediated by microfractures

The current first-line treatment for repairing cartilage defects in clinical practice is the creation of microfractures (MF) to stimulate the release of mesenchymal stem cells (MSCs); however, this method has many limitations. Recent studies have found that MSC-derived extracellular vesicles (MSC-EVs) play an important role in tissue regeneration. This study aimed to verify whether MSC-EVs promote cartilage damage repair mediated by MFs and to explore the repair mechanisms. In vitro experiments showed that human umbilical cord Wharton’s jelly MSC-EVs (hWJMSC-EVs) promoted the vitality of chondrocytes and the proliferation and differentiation ability of bone marrow-derived MSCs. This was mainly because hWJMSC-EVs carry integrin beta-1 (ITGB1), and cartilage and bone marrow-derived MSCs overexpress ITGB1 after absorbing EVs, thereby activating the transforming growth factor-β/Smad2/3 axis. In a rabbit knee joint model of osteochondral defect repair, the injection of different concentrations of hWJMSC-EVs into the joint cavity showed that a concentration of 50 µg/ml significantly improved the formation of transparent cartilage after MF surgery. Extraction of regenerated cartilage revealed that the changes in ITGB1, transforming growth factor-β, and Smad2/3 were directly proportional to the repair of regenerated cartilage. In summary, this study showed that hWJMSC-EVs promoted cartilage repair after MF surgery.Graphical abstract

Injectable Hydrogels Based on Hyaluronic Acid and Gelatin Combined with Salvianolic Acid B and Vascular Endothelial Growth Factor for Treatment of Traumatic Brain Injury in Mice.

Traumatic brain injury (TBI) leads to structural damage in the brain, and is one of the major causes of disability and death in the world. Herein, we developed a composite injectable hydrogel (HA/Gel) composed of hyaluronic acid (HA) and gelatin (Gel), loaded with vascular endothelial growth factor (VEGF) and salvianolic acid B (SAB) for treatment of TBI. The HA/Gel hydrogels were formed by the coupling of phenol-rich tyramine-modified HA (HA-TA) and tyramine-modified Gel (Gel-TA) catalyzed by horseradish peroxidase (HRP) in the presence of hydrogen peroxide (H2O2). SEM results showed that HA/Gel hydrogel had a porous structure. Rheological test results showed that the hydrogel possessed appropriate rheological properties, and UV spectrophotometry results showed that the hydrogel exhibited excellent SAB release performance. The results of LIVE/DEAD staining, CCK-8 and Phalloidin/DAPI fluorescence staining showed that the HA/Gel hydrogel possessed good cell biocompatibility. Moreover, the hydrogels loaded with SAB and VEGF (HA/Gel/SAB/VEGF) could effectively promote the proliferation of bone marrow mesenchymal stem cells (BMSCs). In addition, the results of H&E staining, CD31 and α-SMA immunofluorescence staining showed that the HA/Gel/SAB/VEGF hydrogel possessed good in vivo biocompatibility and pro-angiogenic ability. Furthermore, immunohistochemical results showed that the injection of HA/Gel/SAB/VEGF hydrogel to the injury site could effectively reduce the volume of defective tissues in traumatic brain injured mice. Our results suggest that the injection of HA/Gel hydrogel loaded with SAB and VEGF might provide a new approach for therapeutic brain tissue repair after traumatic brain injury.

Bioengineered MSCCxcr2 transdifferentiated keratinocyte-like cell-derived organoid potentiates skin regeneration through ERK1/2 and STAT3 signaling in diabetic wound

Skin regeneration is severely compromised in diabetic foot ulcers. Allogeneic mesenchymal stem cell (MSC) transplantation is limited due to the poor engraftment, mitogenic, and differentiation potential in the harsh wound microenvironment. Thus, to improve the efficacy of cell therapy, the chemokine receptor Cxcr2 was overexpressed in MSCs (MSCCxcr2). CXCL2/CXCR2 axis induction led to the enhanced proliferation of MSCs through the activation of STAT3 and ERK1/2 signaling. Transcriptional upregulation of FGFR2IIIb (KGF Receptor) promoter by the activated STAT3 and ERK1/2 suggested trans-differentiation of MSCs into keratinocytes. These stable MSCCxcr2 in 2D and 3D (spheroid) cell cultures efficiently transdifferentiated into keratinocyte-like cells (KLCs). An in vivo therapeutic potential of MSCCxcr2 transplantation and its keratinocyte-specific cell fate was observed by accelerated skin tissue regeneration in an excisional splinting wound healing murine model of streptozotocin-induced type 1 diabetes. Finally, 3D skin organoids generated using MSCCxcr2-derived KLCs upon grafting in a relatively avascular and non-healing wounds of type 2 diabetic db/db transgenic old mice resulted in a significant enhancement in the rate of wound closure by increased epithelialization (epidermal layer) and endothelialization (dermal layer). Our findings emphasize the therapeutic role of the CXCL2/CXCR2 axis in inducing trans-differentiation of the MSCs toward KLCs through the activation of ERK1/2 and STAT3 signaling and enhanced skin regeneration potential of 3D organoids grafting in chronic diabetic wounds.