Evaluation of the Effect of NT-3 and Biodegradable Poly-L-lactic Acid Nanofiber Scaffolds on Differentiation of Rat Hair Follicle Stem Cells into Neural Cells In Vitro

Airbrushed nanofibers with bioactive core and antibacterial shell for wound healing application

Acute and chronic wounds are vulnerable to infection and delayed healing and require critical care and advanced wound protection. To overcome the challenges, dual therapy of antibacterial and growth factors will be a novel wound care strategy. The present study explores airbrushed core-shell nanofiber for dual delivery of epidermal growth factor (EGF) and amoxicillin (AMOX) in a sustained manner. A blend of polycaprolactone (PCL)-polyethylene oxide (PEO) was used to prepare the shell compartment for amoxicillin loading and poly-DL-lactide (PDLLA) core for EGF loading by using a customized airbrush setup. Characterization result shows a uniform distribution of nanofibers ranging between 200 and 500 nm in diameter. Amoxicillin loading in the shell compartment offers an initial burst release followed by a sustained release for up to 14 days. Whereas EGF in the core part shows a continuous sustained release throughout the release study.In-vitrostudy indicates the biocompatibility of EGF-AMOX loaded core-shell nanofibers with human dermal fibroblast cell (HDF) cells and a higher cellular proliferation compared to control samples. Gene expression data show an increase in fold change of collagen I and tropoelastin expression, indicating the regenerative properties of EGF-AMOX encapsulated nanofiber. The combination of bioactive core (EGF) and antibiotic shell (amoxicillin) in an airbrushed nanofibrous scaffold is a novel approach, which is the first time explored to deliver sustainable therapy to treat skin wounds. Our results demonstrate that PCL-PEO-Amoxicillin/PDLLA-EGF-loaded core-shell nanofibers are promising dual therapy scaffolds to deliver effective skin wound care, with the possibility of direct deposition on the wound.

Hair Follicle Stem Cells for Tissue Regeneration

With the positive outcomes of various cell therapies currently under pre-clinical and clinical studies, there is a significant interest in novel stem cell sources with unique therapeutic properties. Studies over the past two decades or so demonstrated the feasibility to isolate multipotent/pluripotent stem cells from hair follicles. The easy accessibility, high proliferation and differentiation ability as well as lack of ethical concerns associated with this stem cell source make hair follicle stem cells (HFSCs) attractive candidate for cell therapy and tissue engineering. This review discusses the various stem cell types identified in rodent and human hair follicles and ongoing studies on the potential use of HFSCs for skin, bone, cardio-vascular, and nerve tissue engineering.

Hair follicle stem cells promote cutaneous wound healing through the SDF-1α/CXCR4 axis: an animal model

OBJECTIVE

An appropriate source of adult stem cells for therapeutic use is stem cells deriving from the hair follicle bulge. Following injury, ischaemic tissues produce a variety of cytokines and growth factors that are essential for tissue repair. This study sought to investigate the temporal effects of hair follicle bulge stem cells (HFSCs) on cutaneous wound healing in rats using the SDF-1α/CXCR4 axis.

METHOD

HFSCs obtained from rat vibrissa, labeled with DiI and then special markers, were detected using flow cytometry. The animals were divided into five groups: control (non-treated, n=18), sham (PBS, n=18), AMD (treated with AMD3100, n=18), HFSC + AMD (treated with HFSCs + AMD3100, n=18) and HFSC (treated with HFSCs, n=18). A full-thickness excisional wound model was created and DiI-labeled HFSCs were injected around the wound bed. Wound healing was recorded with digital photographs. The animals were sacrificed 3, 7 and 14 days after the surgery and were used for histological (H&E, Masson's trichrome staining) and molecular (ELISA and q-PCR) assays.

RESULTS

The flow cytometry results demonstrated that HFSCs were CD34-positive, nestin-positive, but Kr15-negative. The morphological analysis of the HFSC-treated wounds showed accelerated wound closure. The histological analysis of the photomicrographs exhibited more re-epithelialisation and dermal structural regeneration in the HFSC-treated wounds compared with the control group. In the HFSC + AMD group, the histological parameters improved on the same days, but showed a significant decrease compared with the HFSC group in all the days assayed. In the AMD group, there was a significant reduction in the noted parameters. qRT-PCR and ELISA showed a high expression level of SDF-1α, CXCR4 and VEGFR-2 in the HFSC-treated wounded skin tissue, but the expression of CXCR4 and VEGFR-2 showed a significant reduction in the HFSC + AMD group compared with the HFSC group.

CONCLUSIONS

Based on the findings of this study, HFSC transplantation affects wound closure parameters and the expression of SDF-1α and CXCR4. As the SDF-1α expression level increases in the injured area, the HFSCs contribute to wound repair through the SDF-1α/CXCR4 axis. This result is extremely valuable because it raises the possibility of wounds healed by isolating autologous HFSCs from the patient.

Poly (L-lactic acid) nanofibrous scaffolds support the proliferation and neural differentiation of mouse neural stem and progenitor cells

BACKGROUND

The distribution and growth of cells on nanofibrous scaffolds seem to be an indispensable precondition in cell tissue engineering. The potential use of biomaterial scaffolds in neural stem cell therapy is increasingly attracting attention.

AIM

In this study, we produced porous nanofibrous scaffolds fabricated from random poly-L-lactic acid (PLLA) to support neurogenic differentiation of neural stem and progenitor cells (NSPCs), isolated from the subventricular zone (SVZ) of the adult mouse brain.

METHODS

The viability and proliferation of the NSPCs on the nanofibrous PLLA scaffold were also tested by nuclear staining with 4, 6-diamidino-2-phenylindole dihydrochloride (DAPI), 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay and scanning electron microscopy (SEM). To investigate the differentiation potential of NSPCs on the scaffolds, the cells were treated with a neurogenic differentiation medium, and immunostaining was done to detect neuronal and glial cells after 14 and 21 days of cultivation. Furthermore, the morphology of differentiated cells on the scaffold was examined using SEM.

RESULTS

The DAPI staining revealed the proliferation of NSPCs onto the surface of the nanofibrous PLLA scaffold. DAPI-positive cells were counted on days 2 and 5 after cultivation. The mean number of cells in each microscopic field was significantly (p < .05) increased (51 ± 19 on day 2 compared to 77 ± 25 cells on day 5). The results showed that the cell viability on PLLA scaffolds significantly increased compared to control groups. Moreover, cell viability was significantly increased 5 days after culturing (262.3 ± 50.2) as compared to 2 days culture in Vitro (174.2 ± 28.3, p < .05). Scanning electron micrographs also showed that the NSPCs adhered and differentiated on PLLA scaffolds. We found that the neural cell markers, microtubule-associated protein 2 (MAP2) and glial fibrillary acidic protein (GFAP), were expressed in NSPCs seeded on random PLLA scaffolds after 21 days of cultivation.

CONCLUSION

These results suggest that the PLLA nano-scaffolds, due to their biocompatible property, are an appropriate structure for the proliferation, differentiation, and normal growth of NSPCs.

Neurotrophin-3-Loaded Multichannel Nanofibrous Scaffolds Promoted Anti-Inflammation, Neuronal Differentiation, and Functional Recovery after Spinal Cord Injury

The clinical therapeutics for nerve tissue regeneration and functional recovery after spinal cord injury (SCI) are very limited because of the complex biological processes and inhibitory microenvironment. Advanced biomaterials are highly desired to avoid severe secondary damage and provide guidance for axonal regrowth. Multichannel nanofibrous scaffolds were modified with gelatin and cross-linked by genipin. The gelatin-coated nanofibers exhibited strong binding affinity with neurotrophin-3, which underwent a well-controlled release and highly promoted neuronal differentiation and synapse formation of the seeded neural stem cells. The nanofibrous scaffolds fabricated by combinatorial biomaterials were implanted into complete transected spinal cords in rats. Not only were the inflammatory responses and collagen/astrocytic scar formation limited, but the functional neurons and remyelination were facilitated postsurgery, leading to highly improved functional restoration. This nanofibrous scaffold with high specific surface area can be easily modified with biomolecules, which was proven to be effective for nerve regeneration after transected SCI, and provided a springboard for advanced scaffold design in clinical applications.

Construction of a NT-3 sustained-release system cross-linked with an acellular spinal cord scaffold and its effects on differentiation of cultured bone marrow mesenchymal stem cells

OBJECTIVE

This study sought to promote the adhesion, proliferation and differentiation of rat bone marrow mesenchymal stem cells by constructing a neurotrophin-3 (NT-3) sustained-release system cross-linked with an acellular spinal cord scaffold.

METHODS

1-Ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride (EDC) chemistry combined with chemical extraction was used to construct an acellular spinal cord scaffold. The decellularization completion was validated. An EDC cross-linking method was used to construct the NT-3 cross-linked acellular spinal scaffold. ELISA was used to verify sustained release of NT-3; the dorsal root ganglion method was used to verify the biological activity of the sustained-release NT-3. DAPI staining was used to confirm the adhesion of the cultured rat bone marrow mesenchymal stem cells (P3) to the NT-3 scaffold, and cell counting kit-8 (CCK-8) analysis was used to verify the cellular proliferation after 24 h and 48 h of culture. Immunohistochemistry was used to confirm the differentiation of the bone marrow cells into neuron-like cells.

RESULTS

An NT-3 sustained-release system cross-linked to an acellular spinal cord scaffold was successfully constructed. Sustained-release NT-3 could persist for 35 days and had biological activity for at least 21 days. It could promote the adhesion, proliferation and differentiation of rat bone marrow mesenchymal stem cells.

CONCLUSION

As a composite scaffold, an NT-3 sustained-release system cross-linked with an acellular spinal cord scaffold has potential applications for tissue engineering.

In vitro induction effect of 1,25(OH)2D3 on differentiation of hair follicle stem cell into keratinocyte

Background

Stem cells are characterized by self-renewal and differentiation capabilities. The bulge hair follicle stem cells (HFSCs) are able to convert to epithelial components. The active metabolite of vitamin D, 1,25(OH)₂D₃, plays important roles in this differentiation process. In the present study has found that 1,25(OH)₂D₃ induces the HFSCs differentiation into keratinocyte.

Methods

HFSCs are isolated from rat whiskers and cultivated in DMEM medium. To isolate bulge stem cell population, flow cytometry and immunocytochemistry using K15, CD34 and nestin biomarkers were performed. In order to accelerate the HFSCs differentiation into keratinocyte, HFSCs were treated with 10⁻¹² M, 1,25(OH)₂D₃ every 48 h for a week.

Results

Immunocytochemistry results showed that bulge stem cells are nestin and CD34 positive but K15 negative before differentiation. Subsequently flow cytometry results, showed that the expression of nestin, CD34 and K15 were 70.96%, 93.03% and 6.88% respectively. After differentiation, the immunocytochemical and flow cytometry results indicated that differentiated cells have positive reaction to K15 with 68.94% expression level.

Conclusion

It was concluded that 10⁻¹² M, 1,25(OH)₂D₃ could induce the HFSCs differentiation into keratinocytes.

Knockdown of α-synuclein in cerebral cortex improves neural behavior associated with apoptotic inhibition and neurotrophin expression in spinal cord transected rats

Spinal cord injury (SCI) often causes severe functional impairment with poor recovery. The treatment, however, is far from satisfaction, and the mechanisms remain unclear. By using proteomics and western blot, we found spinal cord transection (SCT) resulted in a significant down-regulation of α-synuclein (SNCA) in the motor cortex of SCT rats at 3 days post-operation. In order to detect the role of SNCA, we used SNCA-ORF/shRNA lentivirus to upregulate or knockdown SNCA expression. In vivo, SNCA-shRNA lentivirus injection into the cerebral cortex motor area not only inhibited SNCA expression, but also significantly enhanced neurons' survival, and attenuated neuronal apoptosis, as well as promoted motor and sensory function recovery in hind limbs. While, overexpression SNCA exhibited the opposite effects. In vitro, cortical neurons transfected with SNCA-shRNA lentivirus gave rise to an optimal neuronal survival and neurite outgrowth, while it was accompanied by reverse efficiency in SNCA-ORF group. In molecular level, SNCA silence induced the upregulation of Bcl-2 and the downregulation of Bax, and the expression of NGF, BDNF and NT3 was substantially upregulated in cortical neurons. Together, endogenous SNCA play a crucial role in motor and sensory function regulation, in which, the underlying mechanism may be linked to the regulation of apoptosis associated with apoptotic gene (Bax, Bcl2) and neurotrophic factors expression (NGF, BDNF and NT3). These finds provide novel insights to understand the role of SNCA in cerebral cortex after SCT, and it may be as a novel treatment target for SCI repair in future clinic trials.

The role of biodegradable engineered random polycaprolactone nanofiber scaffolds seeded with nestin-positive hair follicle stem cells for tissue engineering

Background:

Tissue engineering is a new approach to reconstruction and/or regeneration of lost or damaged tissue. The purpose of this study was to fabricate the polycaprolactone (PCL) random nanofiber scaffold as well as evaluation of the cell viability, adhesion, and proliferation of rat nestin-positive hair follicle stem cells (HFSCs) in the graft material using electrospun PCL nanofiber scaffold in regeneration medicine.

Materials and Methods:

The bulge HFSCs was isolated from rat whiskers and cultivated in Dulbecco's modified Eagle's medium/F12. To evaluate the biological nature of the bulge stem cells, flow cytometry using nestin, CD34 and K15 antibodies was performed. Electrospinning was used for the production of PCL nanofiber scaffolds. Furthermore, scanning electron microscopy (SEM) for HFSCs attachment, infiltration, and morphology, 3-(4, 5-di-methylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay for cell viability and cytotoxicity, tensile strength of the scaffolds mesh, and histology analysis were used.

Results:

Flow cytometry showed that HFSCs were nestin and CD34 positive but K15 negative. The results of the MTT assay showed cell viability and cell proliferation of the HFSCs on PCL nanofiber scaffolds. SEM microscopy photographs indicated that HFSCs are attached and spread on PCL nanofiber scaffolds. Furthermore, tensile strength of the scaffolds mesh was measured.

Conclusion:

The results of this study revealed that modified PCL nanofiber scaffolds are suitable for HFSCs seeding, attachment, and proliferation. Furthermore, HFSCs are attached and proliferated on PCL nanofiber scaffolds.

Hair follicle stem cells: In vitro and in vivo neural differentiation

Hair follicle stem cells (HFSCs) normally give rise to keratinocytes, sebocytes, and transient amplifying progenitor cells. Along with the capacity to proliferate rapidly, HFSCs provide the basis for establishing a putative source of stem cells for cell therapy. HFSCs are multipotent stem cells originating from the bulge area. The importance of these cells arises from two important characteristics, distinguishing them from all other adult stem cells. First, they are accessible and proliferate for long periods. Second, they are multipotent, possessing the ability to differentiate into mesodermal and ectodermal cell types. In addition to a developmental capacity in vitro, HFSCs display an ability to form differentiated cells in vivo. During the last two decades, numerous studies have led to the development of an appropriate culture condition for producing various cell lineages from HFSCs. Therefore, these stem cells are considered as a novel source for cell therapy of a broad spectrum of neurodegenerative disorders. This review presents the current status of human, rat, and mouse HFSCs from both the cellular and molecular biology and cell therapy perspectives. The first section of this review highlights the importance of HFSCs and in vitro differentiation, while the final section emphasizes the significance of cell differentiation in vivo.