Transfection of gene regulation nanoparticles complexed with pDNA and shRNA controls multilineage differentiation of hMSCs

Factors affecting osteogenesis and chondrogenic differentiation of mesenchymal stem cells in osteoarthritis

Osteoarthritis (OA) is a common degenerative joint disease that often involves progressive cartilage degeneration and bone destruction of subchondral bone. At present, clinical treatment is mainly for pain relief, and there are no effective methods to delay the progression of the disease. When this disease progresses to the advanced stage, the only treatment option for most patients is total knee replacement surgery, which causes patients great pain and anxiety. As a type of stem cell, mesenchymal stem cells (MSCs) have multidirectional differentiation potential. The osteogenic differentiation and chondrogenic differentiation of MSCs can play vital roles in the treatment of OA, as they can relieve pain in patients and improve joint function. The differentiation direction of MSCs is accurately controlled by a variety of signaling pathways, so there are many factors that can affect the differentiation direction of MSCs by acting on these signaling pathways. When MSCs are applied to OA treatment, the microenvironment of the joints, injected drugs, scaffold materials, source of MSCs and other factors exert specific impacts on the differentiation direction of MSCs. This review aims to summarize the mechanisms by which these factors influence MSC differentiation to produce better curative effects when MSCs are applied clinically in the future.

PSAT1 positively regulates the osteogenic lineage differentiation of periodontal ligament stem cells through the ATF4/PSAT1/Akt/GSK3β/β-catenin axis

BACKGROUND

Periodontal ligament stem cells (PDLSCs) are important seed cells for tissue engineering to realize the regeneration of alveolar bone. Understanding the gene regulatory mechanisms of osteogenic lineage differentiation in PDLSCs will facilitate PDLSC-based bone regeneration. However, these regulatory molecular signals have not been clarified.

METHODS

To screen potential regulators of osteogenic differentiation, the gene expression profiles of undifferentiated and osteodifferentiated PDLSCs were compared by microarray and bioinformatics methods, and PSAT1 was speculated to be involved in the gene regulation network of osteogenesis in PDLSCs. Lentiviral vectors were used to overexpress or knock down PSAT1 in PDLSCs, and then the proliferation activity, migration ability, and osteogenic differentiation ability of PDLSCs in vitro were analysed. A rat mandibular defect model was built to analyse the regulatory effects of PSAT1 on PDLSC-mediated bone regeneration in vivo. The regulation of PSAT1 on the Akt/GSK3β/β-catenin signalling axis was analysed using the Akt phosphorylation inhibitor Ly294002 or agonist SC79. The potential sites on the promoter of PSAT1 that could bind to the transcription factor ATF4 were predicted and verified.

RESULTS

The microarray assay showed that the expression levels of 499 genes in PDLSCs were altered significantly after osteogenic induction. Among these genes, the transcription level of PSAT1 in osteodifferentiated PDLSCs was much lower than that in undifferentiated PDLSCs. Overexpressing PSAT1 not only enhanced the proliferation and osteogenic differentiation abilities of PDLSCs in vitro, but also promoted PDLSC-based alveolar bone regeneration in vivo, while knocking down PSAT1 had the opposite effects in PDLSCs. Mechanistic experiments suggested that PSAT1 regulated the osteogenic lineage fate of PDLSCs through the Akt/GSK3β/β-catenin signalling axis. PSAT1 expression in PDLSCs during osteogenic differentiation was controlled by transcription factor ATF4, which is realized by the combination of ATF4 and the PSAT1 promoter.

CONCLUSION

PSAT1 is a potential important regulator of the osteogenic lineage differentiation of PDLSCs through the ATF4/PSAT1/Akt/GSK3β/β-catenin signalling pathway. PSAT1 could be a candidate gene modification target for enhancing PDLSCs-based bone regeneration.

Tendon microstructural disruption promotes tendon-derived stem cells to express chondrogenic genes by activating endoplasmic reticulum stress

The erroneous differentiation of tendon-derived stem cells (TDSCs) into adipocytes, chondrocytes, and osteoblasts is believed to play an important role in the development of tendinopathy. However, the regulatory mechanisms of TDSC differentiation remain unclear. The aim of this study is to investigate the contribution and mechanism of the tendon microstructural disruption to the differentiation of TDSCs. Bovine Achilles tendons were sliced. The tendon slices were stretched with different tensile strains to mimic the tendon structure alteration at various scales. The TDSCs were cultured on the tendon slices. The differentiation of TDSCs and endoplasmic reticulum (ER) stress in the TDSCs were investigated with quantitative reverse transcription polymerase chain reaction, immunostaining and western blot. The effect of ER stress inhibition on chondrogenic differentiation of the TDSCs was further investigated. The structural alteration did not affect the viability of TDSCs. However, the structural alteration of tendon slices with 6.4% strain promoted TDSCs to express the chondrogenic genes. ER stress-related markers, ATF-4 and PERK, were also upregulated. With the inhibition of ER stress, the expression of ATF-4 and the chondrogenic gene SOX9 of TDSCs were inhibited. The study indicated that tendon microdamage could induce the chondrogenic differentiation of TDSCs through triggering ER stress to activate ATF-4 and SOX9 subsequently.

Biomaterial-assisted biotherapy: A brief review of biomaterials used in drug delivery, vaccine development, gene therapy, and stem cell therapy

Biotherapy has recently become a hotspot research topic with encouraging prospects in various fields due to a wide range of treatments applications, as demonstrated in preclinical and clinical studies. However, the broad applications of biotherapy have been limited by critical challenges, including the lack of safe and efficient delivery systems and serious side effects. Due to the unique potentials of biomaterials, such as good biocompatibility and bioactive properties, biomaterial-assisted biotherapy has been demonstrated to be an attractive strategy. The biomaterial-based delivery systems possess sufficient packaging capacity and versatile functions, enabling a sustained and localized release of drugs at the target sites. Furthermore, the biomaterials can provide a niche with specific extracellular conditions for the proliferation, differentiation, attachment, and migration of stem cells, leading to tissue regeneration. In this review, the state-of-the-art studies on the applications of biomaterials in biotherapy, including drug delivery, vaccine development, gene therapy, and stem cell therapy, have been summarized. The challenges and an outlook of biomaterial-assisted biotherapies have also been discussed.

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Biomaterials possess unique advantages to improve the efficacy and safety of biotherapy.

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Various types of biomaterials can be used in a wide range of biotherapy.

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The functions of biomaterials can be tuned by changing their inherent properties or the surrounding environment.

Efficient CRISPR-Cas9-based knockdown of RUNX2 to induce chondrogenic differentiation of stem cells

The clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 system recognizes and deletes specific nucleotide sequences in cells for gene editing. This study aimed to edit and knockdown the RUNX2 gene, a key transcription factor that is directly involved in all stages of stem cell differentiation into osteoblasts. The RUNX2 gene was depleted using the CRISPR-Cas9 system to inhibit osteoblast differentiation of stem cells. shRNA vectors targeting RUNX2 were used as a control. The surface of nanoparticles (NPs) was coated with the cationic polymer linear polyethyleneimine. Thereafter, negatively charged CRISPR-Cas9 and shRNA vectors were complexed with positively charged NPs via ionic interactions. Several analytical methods were used to determine the size, surface charge, and morphology of NPs and to characterize the complexed genes. NPs complexed with CRISPR-Cas9 and shRNA vectors were delivered into human mesenchymal stem cells (hMSCs) via endocytosis. The mRNA and protein expression patterns of various genes in hMSCs were measured over time following internalization of NPs complexed with CRISPR-Cas9 and shRNA vectors in two- and three-dimensional culture systems. Knockdown of the RUNX2 gene decreased osteogenic differentiation and increased chondrogenic differentiation of hMSCs. As a result of investigating the efficiency of NPs complexed with CRISPR-Cas9 (CASP-NPs), Runx2 effectively knocked down in mesenchymal stem cells to enhance differentiation into chondrocytes, therefore CASP-NPs proved to be an effective gene carrier in hMSCs.

LncRNA THUMPD3-AS1 enhances the proliferation and inflammatory response of chondrocytes in osteoarthritis

OBJECTIVE

Long noncoding RNAs (lncRNAs) regulate the occurrence and development of osteoarthritis (OA), whereas the biological roles and mechanisms of the lncRNA THUMPD3-AS1 (THUMPD3 antisense RNA 1) in OA remain still unclear. This study described the role and molecular mechanism of lncRNA THUMPD3-AS1 in regulating OA biology.

METHOD

The knee normal and OA cartilage tissues from ten participants were sequenced to reveal the differentially expressed lncRNAs. The interleukin (IL)-1β-stimulated C28/I2 cell served as OA cells. Flow cytometry assays, Western blot, enzyme-linked immunosorbent assays were used for our experiments.

RESULTS

The results revealed that lncRNA THUMPD3-AS1 was downregulated in OA cartilage tissues and IL-1β-stimulated chondrocyte cell line. Overexpression of lncRNA THUMPD3-AS1 alleviated cell apoptosis and facilitated inflammatory responses, whereas knockdown had opposite effects. LncRNA THUMPD3-AS1 markedly increased the cyclin E2, cyclin-dependent kinase 4, B-cell lymphoma 2, tumor necrosis factor-α, nitric oxide, and IL-6 levels, and decreased the caspase-3 level. Furthermore, the target proteins of phosphorylation were identified as nuclear factor-κB p65 and mitogen-activated protein kinase p38, which could be indirectly suppressed by lncRNA THUMPD3-AS1 knockdown.

CONCLUSION

Our findings highlight the different effects of lncRNA THUMPD3-AS1 on cell apoptosis and inflammatory response, which extend the multiple functions of lncRNA epigenetics in OA biology.

Development of a three-layer consecutive gene delivery system for enhanced bone regeneration

This study developed a three-layer consecutive gene delivery system (T-CGDS) for timely gene delivery into human mesenchymal stem cells (hMSCs). The timing of transcription factor expression is important to effectively induce bone differentiation. Therefore, a three-layered nanocomposite was fabricated using differently sized gold nanoparticles to promote bone regeneration and osteogenic differentiation. The core layer comprised 80 nm gold nanoparticles coupled with ATF4 pDNA. Following coating with heparin-conjugated Pluronic F-127 (HP-F127), 50 nm gold nanoparticles coupled with SP7 pDNA were added to fabricate a bi-layer system. After further coating with HP-F127, 20 nm gold nanoparticles combined with RUNX2 pDNA were added. Consequently, a T-CGDS measuring 350-450 nm was fabricated. Genes were released for more than 8 days, while the size of the T-CGDS decreased over time. When the T-CGDS was applied to hMSCs, the gene in the outer layer (RUNX2) was expressed first, followed by those in the middle (SP7) and core (ATF4) layers. The T-CGDS effectively induced bone differentiation and regeneration in vitro and in vivo. Timely delivery of the ATF4 gene to stem cells via the T-CGDS can greatly assist osteogenic differentiation involved in bone regeneration.

Recent Developed Strategies for Enhancing Chondrogenic Differentiation of MSC: Impact on MSC-Based Therapy for Cartilage Regeneration

Articular cartilage is susceptible to damage, but its self-repair is hindered by its avascular nature. Traditional treatment methods are not able to achieve satisfactory repair effects, and the development of tissue engineering techniques has shed new light on cartilage regeneration. Mesenchymal stem cells (MSCs) are one of the most commonly used seed cells in cartilage tissue engineering. However, MSCs tend to lose their multipotency, and the composition and structure of cartilage-like tissues formed by MSCs are far from those of native cartilage. Thus, there is an urgent need to develop strategies that promote MSC chondrogenic differentiation to give rise to durable and phenotypically correct regenerated cartilage. This review provides an overview of recent advances in enhancement strategies for MSC chondrogenic differentiation, including optimization of bioactive factors, culture conditions, cell type selection, coculture, gene editing, scaffolds, and physical stimulation. This review will aid the further understanding of the MSC chondrogenic differentiation process and enable improvement of MSC-based cartilage tissue engineering.

Application of genetic cell-lineage tracing technology to study cardiovascular diseases

Cardiovascular diseases are leading causes that threaten people's life. To investigate cells that are involved in disease development and tissue repair, various technologies have been introduced. Among these technologies, lineage tracing is a powerful tool to track the fate of cells in vivo, providing deep insights into cellular behavior and plasticity. In cardiac diseases, newly formed cardiomyocytes and endothelial cells are found from proliferation of local cells, while fibroblasts and macrophages are originated from diverse cell sources. Similarly, in response to vascular injury, various sources of cells including media smooth muscle cells, endothelium, resident progenitors and bone marrow cells are involved in lesion formation and/or vessel regeneration. In summary, current review summarizes the development of lineage tracing techniques and their utilizations in investigating roles of different cell types in cardiovascular diseases.

Circular RNA SIPA1L1 promotes osteogenesis via regulating the miR-617/Smad3 axis in dental pulp stem cells

BACKGROUND

Bone regeneration is preferred for bone loss caused by tumors, bone defects, fractures, etc. Recently, mesenchymal stem cells are considered as optimistic tools for bone defect therapy. Dental pulp stem cells (DPSCs) are a promising candidate for regenerative medicine and bone regeneration. Our previous study showed that upregulated circSIPA1L1 during osteogenesis of DPSCs is of significance. In this paper, the potential role of circSIPA1L1 in osteogenesis of DPSCs and its underlying mechanisms are explored.

METHODS

The circular structure of circSIPA1L1 was identified by Sanger sequencing and PCR. Regulatory effects of circSIPA1L1 and miR-617 on mineral deposition in DPSCs were assessed by alkaline phosphatase (ALP) and alizarin red S (ARS) staining and in vivo bone formation assay were conducted to verify the biological influences of circSIPA1L1 on DPSCs. Western blot was performed to detect the protein expression of Smad3. Localization of circSIPA1L1 and miR-617 was confirmed by FISH. Dual-luciferase reporter assay and rescue experiments were conducted to investigate the role of the circSIPA1L1/miR-617/Smad3 regulatory axis in osteogenesis of DPSCs.

RESULTS

Sanger sequencing and back-to-back primer experiments confirmed the closed-loop structure of circSIPA1L1. CircSIPA1L1 could promote the committed differentiation of DPSCs. MiR-617 was predicted to be the target binding circSIPA1L1 through MiRDB, miRTarBase, and TargetScan database analyses, which was further confirmed by dual-luciferase reporter assay. FISH results showed that circSIPA1L1 and miR-617 colocalize in the cytoplasm of DPSCs. MiR-617 exerted an inhibitory effect on the osteogenesis of DPSCs. Knockdown of circSIPA1L1 or upregulation of miR-617 downregulated phosphorylated Smad3. In addition, rescue experiments showed that knockdown of miR-617 reversed the inhibitory effect of circSIPA1L1 on osteogenesis of DPSCs.

CONCLUSION

CircRNASIPA1L1 promotes osteogenesis of DPSCs by adsorbing miR-617 and further targeting Smad3.

Human amnion-derived mesenchymal stem cells promote osteogenic differentiation of human bone marrow mesenchymal stem cells via H19/miR-675/APC axis

Bone volume inadequacy is an emerging clinical problem impairing the feasibility and longevity of dental implants. Human bone marrow mesenchymal stem cells (HBMSCs) have been widely used in bone remodeling and regeneration. This study examined the effect of long noncoding RNAs (lncRNAs)-H19 on the human amnion-derived mesenchymal stem cells (HAMSCs)-droved osteogenesis in HBMSCs. HAMSCs and HBMSCs were isolated from abandoned amniotic membrane samples and bone marrow. The coculture system was conducted using transwells, and H19 level was measured by quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR). The mechanism was further verified. We here discovered that osteogenesis of HBMSCs was induced by HAMSCs, while H19 level in HAMSCs was increased during coculturing. H19 had no significant effect on the proliferative behaviors of HBMSCs, while its overexpression of H19 in HAMSCs led to the upregulated osteogenesis of HBMSCs in vivo and in vitro; whereas its knockdown reversed these effects. Mechanistically, H19 promoted miR-675 expression and contributed to the competitively bounding of miR-675 and Adenomatous polyposis coli (APC), thus significantly activating the Wnt/β-catenin pathway. The results suggested that HAMSCs promote osteogenic differentiation of HBMSCs via H19/miR-675/APC pathway, and supply a potential target for the therapeutic treatment of bone-destructive diseases.

Regulation and function of SOX9 during cartilage development and regeneration

Chondrogenesis is a highly coordinated event in embryo development, adult homeostasis, and repair of the vertebrate cartilage. Fate decisions and differentiation of chondrocytes accompany differential expression of genes critical for each step of chondrogenesis. SOX9 is a master transcription factor that participates in sequential events in chondrogenesis by regulating a series of downstream factors in a stage-specific manner. SOX9 either works alone or in combination with downstream SOX transcription factors, SOX5 and SOX6 as chondrogenic SOX Trio. SOX9 is reduced in the articular cartilage of patients with osteoarthritis while highly maintained during tumorigenesis of cartilage and bone. Gene therapy using viral and non-viral vectors accompanied by tissue engineering (scaffolds) is a promising tool to regenerate impaired cartilage. Delivery of SOX9 or chondrogenic SOX Trio into cells produces efficient therapeutic effects on chondrogenesis and this event is facilitated by scaffolds. Non-viral vector-guided delivery systems encapsulated or loaded in mechanically stable solid scaffolds are useful for the regeneration of articular cartilage. Here we review major milestones and most recent studies focusing on regulation and function of chondrogenic SOX Trio, during chondrogenesis and cartilage regeneration, and on the development of advanced technologies in gene delivery with tissue engineering to improve efficiency of cartilage repair process.

Application of Nanomaterials in Regulating the Fate of Adipose-derived Stem Cells

Adipose-derived stem cells are adult stem cells which are easy to obtain and multi-potent. Stem-cell therapy has become a promising new treatment for many diseases, and plays an increasingly important role in the field of tissue repair, regeneration and reconstruction. The physicochemical properties of the extracellular microenvironment contribute to the regulation of the fate of stem cells. Nanomaterials have stable particle size, large specific surface area and good biocompatibility, which has led them being recognized as having broad application prospects in the field of biomedicine. In this paper, we review recent developments of nanomaterials in adipose-derived stem cell research. Taken together, the current literature indicates that nanomaterials can regulate the proliferation and differentiation of adipose-derived stem cells. However, the properties and regulatory effects of nanomaterials can vary widely depending on their composition. This review aims to provide a comprehensive guide for future stem-cell research on the use of nanomaterials.

The recent progresses in shRNA-nanoparticle conjugate as a therapeutic approach

The recent trend of gene therapy is using short hairpin RNA conjugated with different types of nanoparticles. shRNAs have a significant role in gene silencing and have a promising role in treating several genetic and infectious diseases. There are several drawbacks of delivering bare shRNA in the blood as they are fragile in nature and readily degradable. To overcome this problem shRNAs can be conjugated with nanoparticles for a safe deliver. In this article several nanoparticles are mentioned which play significant role in delivery of this payload. On one hand they protect the shRNA from degradation on the other they help to penetrate this large molecule in to the cell. Some of these nanoconjugates are in clinical trials and have a promising role in treatment of diseases.

LncRNA H19 promotes the committed differentiation of stem cells from apical papilla via miR-141/SPAG9 pathway

Long noncoding RNAs (lncRNAs) exert significant roles at transcriptional and post-transcriptional levels. Stem cells from apical papilla (SCAPs) differentiate into dentin/bone-like tissues under certain conditions. So far, whether lncRNA-H19 can affect the proliferative behaviors and osteo/odontogenesis of SCAPs, as well as its specific mechanism remain to be elucidated. Here, SCAPs were isolated and transfected with the lentiviruses or packaging vectors. Our results showed that lncRNA-H19 had no significant effect on the proliferative behaviors of SCAPs, as presented by CCK-8 assay, EdU assay and flow cytometry (FCM). Furthermore, alkaline phosphatase (ALP) activity, alizarin red staining, Western blot assay (WB), quantitative real-time polymerase chain reaction (qRT-PCR) and in vivo bone formation assay were conducted to verify the biological influences of H19 on SCAPs. Overexpression of H19 led to the enhanced osteo/odontogenesis of SCAPs, whereas knockdown of H19 inhibited these effects. Mechanistically, H19 competitively bound to miR-141 and prevented SPAG9 from miRNA-mediated degradation, thus significantly elevating phosphorylated levels of p38 and JNK and facilitating the committed differentiation of SCAPs. Taken together, the osteo/odontogenesis of SCAPs was upregulated by overexpression of H19 via miR-141/SPAG9 pathway.