Growth of human umbilical cord Wharton's Jelly-derived mesenchymal stem cells on the terpolyester poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate)

Resorbable Nanomatrices from Microbial Polyhydroxyalkanoates: Design Strategy and Characterization

From a series of biodegradable natural polymers of polyhydroxyalkanoates (PHAs)-poly-3-hydroxybutyrate (P(3HB) and copolymers containing, in addition to 3HB monomers, monomers of 3-hydroxyvalerate (3HV), 3-hydroxyhexanoate (3HHx), and 4-hydroxybutyrate (4HB), with different ratios of monomers poured-solvent casting films and nanomembranes with oriented and non-oriented ultrathin fibers were obtained by electrostatic molding. With the use of SEM, AFM, and measurement of contact angles and energy characteristics, the surface properties and mechanical and biological properties of the polymer products were studied depending on the method of production and the composition of PHAs. It has been shown in cultures of mouse fibroblasts of the NIH 3T3 line and diploid human embryonic cells of the M22 line that elastic films and nanomembranes composed of P(3HB-co-4HB) copolymers have high biocompatibility and provide adhesion, proliferation and preservation of the high physiological activity of cells for up to 7 days. Polymer films, namely oriented and non-oriented nanomembranes coated with type 1 collagen, are positively evaluated as experimental wound dressings in experiments on laboratory animals with model and surgical skin lesions. The results of planimetric measurements of the dynamics of wound healing and analysis of histological sections showed the regeneration of model skin defects in groups of animals using experimental wound dressings from P(3HB-co-4HB) of all types, but most actively when using non-oriented nanomembranes obtained by electrospinning. The study highlights the importance of nonwoven nanomembranes obtained by electrospinning from degradable low-crystalline copolymers P(3HB-co-4HB) in the effectiveness of the skin wound healing process.

The role of extracellular vesicles in osteoarthritis treatment via microenvironment regulation

Osteoarthritis (OA) is a degenerative joint disease that is common among the middle-aged and older populations, causes patients to experience recurrent pain in their joints and negatively affects their quality of life. Currently, therapeutic options for patients with OA consist of medications to alleviate pain and treat the symptoms; however, due to typically poor outcomes, patients with advanced OA are unlikely to avoid joint replacement. In recent years, several studies have linked disrupted homeostasis of the joint cavity microenvironment to the development of OA. Recently, extracellular vesicles (EVs) have received increasing attention in the field of OA. EVs are natural nano-microcarrier materials with unique biological activity that are produced by cells through paracrine action. They are composed of lipid bilayers that contain physiologically active molecules, such as nucleic acids and proteins. Moreover, EVs may participate in local and distal intercellular and intracellular communication. EVs have also recently been shown to influence OA development by regulating biochemical factors in the OA microenvironmental. In this article, we first describe the microenvironment of OA. Then, we provide an overview of EVs, summarize the main types used for the treatment of OA, and describe their mechanisms. Next, we review clinical studies using EVs for OA treatment. Finally, the specific mechanism underlying the application of miRNA-enriched EVs in OA therapy is described.

Microbial-Derived Polyhydroxyalkanoate-Based Scaffolds for Bone Tissue Engineering: Biosynthesis, Properties, and Perspectives

Polyhydroxyalkanoates (PHAs) are a class of structurally diverse natural biopolyesters, synthesized by various microbes under unbalanced culture conditions. PHAs as biomedical materials have been fabricated in various forms to apply to tissue engineering for the past years due to their excellent biodegradability, inherent biocompatibility, modifiable mechanical properties, and thermo-processability. However, there remain some bottlenecks in terms of PHA production on a large scale, the purification process, mechanical properties, and biodegradability of PHA, which need to be further resolved. Therefore, scientists are making great efforts via synthetic biology and metabolic engineering tools to improve the properties and the product yields of PHA at a lower cost for the development of various PHA-based scaffold fabrication technologies to widen biomedical applications, especially in bone tissue engineering. This review aims to outline the biosynthesis, structures, properties, and the bone tissue engineering applications of PHA scaffolds with different manufacturing technologies. The latest advances will provide an insight into future outlooks in PHA-based scaffolds for bone tissue engineering.

Effect of poly(3-hydroxyalkanoates) as natural polymers on mesenchymal stem cells

Mesenchymal stem cells (MSCs) are stromal multipotent stem cells that can differentiate into multiple cell types, including fibroblasts, osteoblasts, chondrocytes, adipocytes, and myoblasts, thus allowing them to contribute to the regeneration of various tissues, especially bone tissue. MSCs are now considered one of the most promising cell types in the field of tissue engineering. Traditional petri dish-based culture of MSCs generate heterogeneity, which leads to inconsistent efficacy of MSC applications. Biodegradable and biocompatible polymers, poly(3-hydroxyalkanoates) (PHAs), are actively used for the manufacture of scaffolds that serve as carriers for MSC growth. The growth and differentiation of MSCs grown on PHA scaffolds depend on the physicochemical properties of the polymers, the 3D and surface microstructure of the scaffolds, and the biological activity of PHAs, which was discovered in a series of investigations. The mechanisms of the biological activity of PHAs in relation to MSCs remain insufficiently studied. We suggest that this effect on MSCs could be associated with the natural properties of bacteria-derived PHAs, especially the most widespread representative poly(3-hydroxybutyrate) (PHB). This biopolymer is present in the bacteria of mammalian microbiota, whereas endogenous poly(3-hydroxybutyrate) is found in mammalian tissues. The possible association of PHA effects on MSCs with various biological functions of poly(3-hydroxybutyrate) in bacteria and eukaryotes, including in humans, is discussed in this paper.

Biocompatibility Assessment of PLCL-Sericin Copolymer Membranes Using Wharton's Jelly Mesenchymal Stem Cells

Stem cells based tissue engineering requires biocompatible materials, which allow the cells to adhere, expand, and differentiate in a large scale. An ideal biomaterial for clinical application should be free from mammalian products which cause immune reactivities and pathogen infections. We invented a novel biodegradable poly(L-lactic-co-ε-caprolactone)-sericin (PLCL-SC) copolymer membrane which was fabricated by electrospinning. Membranes with concentrations of 2.5 or 5% (w/v) SC exhibited qualified texture characteristics with a noncytotoxic release profile. The hydrophilic properties of the membranes were 35–40% higher than those of a standard PLCL and commercial polystyrene (PS). The improved characteristics of the membranes were due to an addition of new functional amide groups, C=O, N–H, and C–N, onto their surfaces. Degradation of the membranes was controllable, depending on the content proportion of SC. Results of thermogram indicated the superior stability and crystallinity of the membranes. These membranes enhanced human Wharton's jelly mesenchymal stem cells (hWJMSC) proliferation by increasing cyclin A and also promoted cell adhesion by upregulating focal adhesion kinase (FAK). On the membranes, hWJMSC differentiated into a neuronal lineage with the occurrence of nestin. These data suggest that PLCL-SC electrospun membrane represents some properties which will be useful for tissue engineering and medical applications.

Promoting the recovery of injured liver with poly (3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate) scaffolds loaded with umbilical cord-derived mesenchymal stem cells

Cell-based therapies are major focus of current research for treatment of liver diseases. In this study, mesenchymal stem cells were isolated from human umbilical cord Wharton's jelly (WJ-MSCs). Results confirmed that WJ-MSCs isolated in this study could express the typical MSC-specific markers and be induced to differentiate into adipocytes, osteoblasts, and chondrocytes. They could also be induced to differentiate into hepatocyte-like cells. Poly (3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate) (PHBVHHx) is a new member of polyhydroxyalkanoate family and biodegradable polyester produced by bacteria. PHBVHHx scaffolds showed much higher cell attachment and viability than the other polymers tested. PHBVHHx scaffolds loaded with WJ-MSCs were transplanted into liver-injured mice. Liver morphology improved after 30 days of transplantation and looked similar to normal liver. Concentrations of serum alanine aminotransferase and total bilirubin were significantly lower, and albumin was significantly higher on days 14 and 30 in the WJ-MSCs+scaffold group than in the carbon tetrachloride (CCl4) group. Hematoxylin-eosin staining showed that liver had similar structure of normal liver lobules and similar size and shape of normal hepatic cells, and Masson staining demonstrated that liver had less blue staining for collagen after 30 days of transplantation. Real-time reverse transcription-polymerase chain reaction (RT-PCR) showed that the expression of the bile duct epithelial cell gene CK-19 in mouse liver is significantly lower on days 14 and 30 in the WJ-MSCs+scaffold group than in the CCl4 group. Real-time RT-PCR, immunocytochemistry, and periodic acid-Schiff staining showed that WJ-MSCs in scaffolds differentiated into hepatocyte-like cells on days 14 and 30 in the WJ-MSCs+scaffold group. Real-time RT-PCR also demonstrated that WJ-MSCs in scaffolds expressed endothelial cell genes Flk-1, vWF, and VE-cadherin on days 14 and 30 in the WJ-MSCs+scaffold group, indicating that WJ-MSCs also differentiated into endothelial-like cells. These results demonstrated that PHBVHHx scaffolds loaded with WJ-MSCs significantly promoted the recovery of injured liver and could be further studied for liver tissue engineering.

PHBVHHx scaffolds loaded with umbilical cord-derived mesenchymal stem cells or hepatocyte-like cells differentiated from these cells for liver tissue engineering

More attention has recently been focused on the treatment of various kinds of hepatic diseases based on cell-based therapies. In this study, mesenchymal stem cells were isolated from umbilical cord (UC-MSCs). Results confirmed that UC-MSCs could differentiate into adipocytes, osteoblasts and hepatocytes. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate) (PHBVHHx), a new member of polyhydroxyalkanoate (PHA) family, was produced by bacteria. Liver-injured mouse model was established by CCl4 injection. PHBVHHx scaffolds were transplanted into the liver-injured mice. Liver morphology on day 28 post-transplantation of scaffolds loaded with UC-MSCs or hepatocyte-like cells differentiated from UC-MSCs significantly improved and looked similar to the normal liver. Concentrations of albumin (ALB) significantly increased, and total bilirubin (TB) and alanine axminotransferase (ALT) significantly decreased on days 14 and 28 post-transplantation of scaffolds loaded with UC-MSCs or differentiated UC-MSCs. HE staining showed that on day 28 post-transplantation of scaffolds loaded with UC-MSCs or differentiated UC-MSCs, livers had similar tissue structure of normal livers. Masson staining showed that on day 28 post-transplantation of scaffolds loaded with UC-MSCs or differentiated UC-MSCs, livers had less blue staining for collagen deposition compared with the others. These results demonstrated that PHBVHHx scaffolds loaded with UC-MSCs or differentiated UC-MSCs had the similar effect on injured livers and significantly promoted the recovery of injured livers.

A glucose-utilizing strain, Cupriavidus euthrophus B-10646: growth kinetics, characterization and synthesis of multicomponent PHAs

This study investigates kinetic and production parameters of a glucose-utilizing bacterial strain, C. eutrophus B-10646, and its ability to synthesize PHA terpolymers. Optimization of a number of parameters of bacterial culture (cell concentration in the inoculum, physiological activity of the inoculum, determined by the initial intracellular polymer content, and glucose concentration in the culture medium during cultivation) provided cell concentrations and PHA yields reaching 110 g/L and 80%, respectively, under two-stage batch culture conditions. Addition of precursor substrates (valerate, hexanoate, propionate, γ-butyrolactone) to the culture medium enabled synthesis of PHA terpolymers, P(3HB/3HV/4HB) and P(3HB/3HV/3HHx), with different composition and different molar fractions of 3HB, 3HV, 4HB, and 3HHx. Different types of PHA terpolymers synthesized by C. eutrophus B-10646 were used to prepare films, whose physicochemical and physical-mechanical properties were investigated. The properties of PHA terpolymers were significantly different from those of the P3HB homopolymer: they had much lower degrees of crystallinity and lower melting points and thermal decomposition temperatures, with the difference between these temperatures remaining practically unchanged. Films prepared from all PHA terpolymers had higher mechanical strength and elasticity than P3HB films. In spite of dissimilar surface structures, all films prepared from PHA terpolymers facilitated attachment and proliferation of mouse fibroblast NIH 3T3 cells more effectively than polystyrene and the highly crystalline P3HB.

Advances in the applications of polyhydroxyalkanoate nanoparticles for novel drug delivery system

Drug delivery technology is emerging as an interdisciplinary science aimed at improving human health. The controlled delivery of pharmacologically active agents to the specific site of action at the therapeutically optimal rate and dose regimen has been a major goal in designing drug delivery systems. Over the past few decades, there has been considerable interest in developing biodegradable drug carriers as effective drug delivery systems. Polymeric materials from natural sources play an important role in controlled release of drug at a particular site. Polyhydroxyalkanoates, due to their origin from natural sources, are given attention as candidates for drug delivery materials. Biodegradable and biocompatible polyhydroxyalkanoates are linear polyesters produced by microorganisms under unbalanced growth conditions, which have emerged as potential polymers for use as biomedical materials for drug delivery due to their unique physiochemical and mechanical properties. This review summarizes many of the key findings in the applications of polyhydroxyalkanoates and polyhydroxyalkanoate nanoparticles for drug delivery system.

Induced apoptosis of osteoblasts proliferating on polyhydroxyalkanoates

The mechanism study on behaviors of cells influenced by biomaterial surface properties can provide profound guidances for functional tissue engineering scaffolds design. In this study, regulation of integrin-mediated cell-substrate interactions using rat osteoblasts incubated on PHA films was investigated. Compared with tissue culture plate (TCP), poly-3-hydroxybutyrate (PHB), copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate (PHBV) and copolymer of 3-hydroxybutyrate and 3-hydroxyhexanoate (PHBHHx), osteoblasts inoculated on a terpolymer of 3-hydroxybutyrate, 3-hydroxyvalerate and 3-hydroxyhexanoate (PHBVHHx) were found to have higher apoptosis rates. Several integrin subunits in osteoblasts grown on PHBVHHx showed altered expressions. Simultaneously, extracellular matrics (ECM) were also remodeled on the material surface. Osteoblasts showed a higher expression of integrin subunit β3 and αv on PHBVHHx films compared with that on TCP. On the other hand, less vitronectin, osteopontin and fibronectin, the main ligands for integrin β3 were expressed and deposited in ECM. The unligated integrin β3 could recruit caspase-8 to the membrane and activate its downstream signaling which was proven by the caspase-8 activation assay. It was therefore concluded that the induced apoptosis of osteoblasts on PHBVHHx was regulated by recruitment of caspase-8 to the unligated integrin β3.

Improving the attachment and proliferation of umbilical cord mesenchymal stem cells on modified polystyrene by nitrogen-containing plasma

Wharton's jelly mesenchymal stem cells (WJMSCs) are important alternative source of pluripotent cells for several therapeutic purposes. Understanding of adhesion properties of such cells is necessary to regulate the attachment, growth and proliferation on targeted culture surfaces. BCP-K1, a line of WJMSCs, and polystyrene (PS) culture dishes were used as membrane samples. A 13.56 MHz inductively coupled discharge plasma reactor with a mixture of N-containing gas and noble gas was used. This was expected to introduce the more hydrophilic groups on PS surface and enhance the cell adhesion. The plasma-treated PS dishes with the mixed gas of N(2) + He at 50 W and NH(3) + He at 100 W were reactive towards BCP-K1. Cellular adhesion and proliferation was significantly twice as efficient on the treated surfaces than on PS dishes. BCP-K1 also secreted more focal adhesion kinase to adhere and proliferate when cultured on N(2)-treated PS dishes than on the NH(3)-treated PS dishes. Stable stemness markers were detected, including CD105, CD9 and SSEA-4, expressed on BCP-K1 growing on the modified PS dish surfaces, during 7 days of culturing. The presence of -NH(2) groups on the PS dish surface were revealed by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. A large amount of oxygen- and nitrogen-containing functional groups, up to 9.0 %, were introduced by NH(3) plasma and N(2) plasma. The functional groups introduced on to the PS surfaces were clearly the key factors which enhanced WJMSCs attachment and stemness stability.

Differentiation of umbilical cord mesenchymal stem cells into steroidogenic cells in comparison to bone marrow mesenchymal stem cells

OBJECTIVES

Human umbilical cord can be obtained easily and it represents a non-controversial source of mesenchymal stem cells (MSCs) and umbilical cord Wharton's jelly-derived MSCs (UC-MSCs) have low immunogenicity. In this study, UC-MSCs were induced to become steroidogenic cells and compared to bone marrow-derived MSCs (BM-MSCs).

MATERIAL AND METHODS

UC-MSCs and BM-MSCs were induced to differentiate into steroidogenic cells by infection with adenovirus containing SF-1. Expression of steroidogenic mRNA was analysed by real-time RT-PCR and steroid secretion was detected by ELISA testing. Viability of differentiated cells was examined using cell counting kit-8 assay.

RESULTS

Both UC-MSCs and BM-MSCs expressed typical MSC markers and could differentiate into adipocytes, osteocytes and chondrocytes and both cell types had the potential to differentiate into steroidogenic cells after being infected with adenovirus containing SF-1 cDNA. However, UC-MSCs had significantly higher proliferative potential than BM-MSCs and differentiated UC-MSCs had significantly higher expression of all steroidogenic mRNAs tested over those of differentiated BM-MSCs; this included P450 side-chain cleavage enzyme, 3β-HSD, 17β-HSD type 3, LH-R, ACTH-R, P450c21 and CYP17. In addition, differentiated UC-MSCs secreted significantly more steroidogenic hormones than differentiated BM-MSCs, including testosterone and cortisol. Furthermore, differentiated UC-MSCs had significantly higher cell viability than differentiated BM-MSCs.

CONCLUSIONS

UC-MSCs had significantly higher potential of steroidogenic differentiation than BM-MSCs; thus, UC-MSCs could be favourable cells of choice for cell-based therapy for steroidogenic insufficiency compared to BM-MSCs.

Transcriptional regulation of oct4 in human bone marrow mesenchymal stem cells

Oct4 is a key transcription factor to maintain self-renewal and undifferentiated state of embryonic stem cells. Site 2A located between -2,546 and -2,530 bp and site 2B between -2,500 and -2,486 bp of human Oct4 gene were shown to be sufficient for inducing Oct4 gene expression in embryonic stem cells. Site 2B contains octamer element capable of binding to factor Oct4 and sox element capable of binding to factor Sox2. So far, little is known about the molecular mechanisms for the control of growth and differentiation of adult stem cells including bone marrow-derived mesenchymal stem cells (BM-MSCs), and it is important to understand how Oct4 expression is regulated in BM-MSCs. This study showed that Oct4 and Sox2 genes were expressed in undifferentiated BM-MSCs and BM-MSCs on day 7 but not on days 14 and 21 following osteogenic induction. Site 2A of Oct4 gene, not site 2B, activated the expression of reporter genes luciferase and enhanced green fluorescent protein in undifferentiated BM-MSCs but not in BM-MSCs following osteogenic differentiation. These data demonstrate that site 2A is sufficient for inducing the expression of Oct4 gene in BM-MSCs, and site 2B is not required. Electrophoretic mobility shift assay showed the 2 shifted bands with site 2B probe and the addition of Oct4 and Sox2 antibodies did not supershift these 2 bands. As probes containing mutated octamer and sox elements of site 2B still gave the same 2 shifted bands, it was concluded that they did not result from the binding to site 2B probe by factors Oct4 and Sox2. These bands may be due to the binding of 2 unknown transcription factors.

The behaviour of neural stem cells on polyhydroxyalkanoate nanofiber scaffolds

Polyhydroxyalkanoates (PHA) have demonstrated their potentials as medical implant biomaterials. Neural stem cells (NSCs) grown on/in PHA scaffolds may be useful for repairing central nervous system (CNS) injury. To investigate this possibility, nanofiber matrices (scaffolds) prepared from several PHA via a novel phase separation process were studied to mimic natural extracellular matrix (ECM), and rat-derived NSCs grown in the PHA matrices were characterized regarding their in vitro differentiation behaviors. All three PHA materials including poly(3-hydroxybutyrate) (PHB), copolymer of 3-hydroxybutyrate and 4-hydroxybutyrate (P3HB4HB), and copolymer of 3-hydroxybutyrate and 3-hydroxyhexanoate (PHBHHx) supported NSC growth and differentiation both on their 2D films and 3D matrices. Among three PHA nanofiber matrices, PHBHHx one showed the strongest potentials to promote NSC differentiation into neurons which is beneficial for CNS repair. Compared to the 2D films, 3D nanofiber matrices appeared to be more suitable for NSC attachment, synaptic outgrowth and synaptogenesis. It was suggested that PHBHHx nanofiber scaffolds (matrices) that promote NSC growth and differentiation, can be developed for treating central nervous system injury.