Differentiation of Bone Marrow Mesenchymal Stem Cells to Cardiomyocyte-Like Cells Is Regulated by the Combined Low Dose Treatment of Transforming Growth Factor-β1 and 5-Azacytidine

Effect of miR-18a-5p, miR-19a-3p, and miR-20a-5p on In Vitro Cardiomyocyte Differentiation of Human Endometrium Tissue-Derived Stem Cells Through Regulation of Smad4 Expression

Background

Smad4 regulates the expression of the genes required for heart homeostasis. Regarding the central role of microRNAs in cardiac biology, we investigated the expression of the three Smad4-targeting miRNAs, namely miR-18a-5p, miR-19a-3p, and miR-20a-5p, as well as Smad4 during differentiation of human endometrium-derived mesenchymal stem cells (hEMSCs) into cardiomyocytes (CMs).

Methods

To evaluate mesenchymal phenotype and multi-lineage differentiation ability of hEMSCs, immunophenotyping by flow cytometry and differentiation into osteoblasts and adipocytes were performed, respectively. For transdifferentiation into CMs, hEMSCs were exposed to a cardiomyogenic medium composed of 5-aza and bFGF for 30 days. The comparison between transcriptional expression levels of Nkx2-5, GATA4, Smad4, TNNT2, TBX5, miR-18a-5p, miR-19a-3p, and miR-20a-5p by qRT-PCR, as well as protein levels of Nkx2-5, Smad4, and cTnT by immunofluorescence staining, was conducted in every 6 days.

Results

In vitro, the mesenchymal stem cell phenotype of hEMSCs and their potency for differentiation into other MSCs were confirmed. Differentiated hEMSCs had morphological characteristics of CMs. The percentage of positive cells for Nkx2-5, Smad4, and cTnT proteins was increased following induction and culminated on the 24th day. Also, mRNA levels of Nkx2-5, GATA4, Smad4, TNNT2, and TBX5 exhibited the same trend. The expression of investigated miRNAs was significantly decreased sequentially. A significant negative correlation between expressions of Smad4 and investigated miRNAs was observed.

Conclusion

Our results indicate that miR-18a-5p, miR-19a-3p, and miR-20a-5p are involved in the cardiac differentiation propensity of hEMSCs potentially by regulation of Smad levels. Although, more mechanistic experiments are required to confirm this idea.

Novel fabrication of bioengineered injectable chitosan hydrogel loaded with conductive nanoparticles to improve therapeutic potential of mesenchymal stem cells in functional recovery after ischemic myocardial infarction

In recent decades, myocardial regeneration through stem cell transplantation and tissue engineering has been viewed as a promising technique for treating myocardial infarction. As a result, the researcher attempts to see whether co-culturing modified mesenchymal stem cells with Au@Ch-SF macro-hydrogel and H9C2 may help with tissue regeneration and cardiac function recovery. The gold nanoparticles (Au) incorporated into the chitosan-silk fibroin hydrogel (Au@Ch-SF) were validated using spectral and microscopic examinations. The most essential elements of hydrogel groups were investigated in detail, including weight loss, mechanical strength, and drug release rate. Initially, the cardioblast cells (H9C2 cells) was incubated with Au@Ch-SF macro-hydrogel, followed by mesenchymal stem cells (2 × 10⁵) were transplanted into the Au@Ch-SF macro-hydrogel+H9C2 culture at the ratio of 2:1. Further, cardiac phenotype development, cytokines expression and tissue regenerative performance of modified mesenchymal stem cells treatment were studied through various in vitro and in vivo analyses. The Au@Ch-SF macro-hydrogel gelation time was much faster than that of Ch and Ch-SF hydrogels, showing that Ch and SF exhibited greater intermolecular interactions. The obtained Au@Ch-SF macro-hydrogel has no toxicity on mesenchymal stem cells (MS) or cardiac myoblast (H9C2) cells, according to the biocompatibility investigation. MS cells co-cultured with Au@Ch-SF macro-hydrogel and H9C2 cells also stimulated cardiomyocyte fiber restoration, which has been confirmed in myocardial infarction rats using -MHC and Cx43 myocardial indicators. We developed a novel method of co-cultured therapy using MS cells, Au@Ch-SF macro-hydrogel, and H9C2 cells which could promote the regenerative activities in myocardial ischemia cells. These study findings show that co-cultured MS therapy might be effective for the treatment of myocardial injury.

Glukagon benzeri peptit-1'in yağ doku kaynaklı mezenkimal kök hücrelerinin kardiyomiyositlere dönüşmesi üzerindeki etkisi

Amaç: Mezenkimal kök hücreler, çeşitli protokoller kullanılarak in vitro koşullarda kolaylıkla kardiyomiyositlere farklılaşabilir. Ancak bu protokollerde kullanılan ajanların hücre canlılığı üzerinde bazı olumsuz etkileri olduğu bildirilmiştir. Azasitidin mezenkimal kök hücreleri kalp kası hücrelerine farklandırmak için kullanılmaktadır. Bu çalışmanın amacı, bir GLP-1 reseptör agonisti olan Eksenatid'in insan yağ dokusu kaynaklı kök hücrelerinin kardiyomiyositlere farklılaşması ve canlılığı üzerindeki etkilerini araştırmaktır. Gereç ve Yöntem: Azasitidin ve Eksenatid'in insan yağ doku kaynaklı mezenkimal kök hücreler üzerinde hücre canlılığı ve proliferasyonu üzerindeki etkileri ile sitotoksisite testleri yapıldı. Farklılanma protokolü için, hücreler dört hafta boyunca Azasitidin ve Eksenatid ile inkübe edildi. Hücrelerin morfolojik değişiklikleri izlendi ve kardiyomiyojenik farklılaşma belirteçlerinin (cTnI, GATA4 ve MYH7) ekspresyonları immünohistokimyasal olarak değerlendirildi. Ayrıca kültürlerdeki kardiyak troponin I (cTnI) seviyeleri enzime bağlı immünosorbent testi kullanılarak ölçüldü. Veriler, tek yönlü varyans analizi (ANOVA) ve post-hoc testi ile değerlendirildi. Bulgular: İnsan yağ doku kaynaklı mezenkimal kök hücreler üzerine Azasitidin uygulaması, kontrole grubuna kıyasla hücre canlılığını önemli ölçüde azaltırken (%54.4) hücrelerin Azasitidin+Eksenatid ile uygulaması doza bağlı bir şekilde hücre ölümünü önledi. Azasitidin ve Eksenatid uygulanan hücreler, kardiyomiyojenik farklılaşma ile uyumlu önemli morfolojik değişiklikler ve kardiyomiyojenik belirteçlerde artış gösterdi. Ayrı ayrı ve birlikte uygulama yapılan gruplarda cTnI seviyeleri kontrole göre anlamlı derecede yüksek bulundu. Sonuç: Bu bulgular GLP-1 reseptör agonisti Eksenatid'in, Azasitidin uygulamasının neden olduğu hücre hasarını azaltarak İnsan yağ doku kaynaklı mezenkimal kök hücrelerin kardiyomiyojenik farklılaşması üzerinde faydalı etkileri olabileceğini düşündürmektedir.

Polycaprolactone-co-polylactic acid nanofiber scaffold in combination with 5-azacytidine and transforming growth factor-β to induce cardiomyocyte differentiation of adipose-derived mesenchymal stem cells

Adipose-derived mesenchymal stem cells (Ad-MSCs) are promising candidates for cardiac repair/regeneration. The application of copolymer nanoscaffolds has received great attention in tissue engineering to support differentiation and functional tissue organization toward effective tissue regeneration. The objective of the current study was to develop functional and bioactive scaffolds by combining polycaprolactone (PCL) and polylactic acid (PLA) for cardiomyocyte differentiation of human Ad-MSC (hAd-MSCs) in the absence or presence of 5-azacytidine and transforming growth factor-β (TGF-β). To that end, the human MSCs were extracted from human adipose tissue (AD). The cardiomyocyte differentiation potency of hAd-MSCs was evaluated on the novel synthetic PCL/PLA nanofiber scaffolds prepared in the absence and presence of 5-azacytidine and TGF-β supplements. A PCL/PLA nanofibrous scaffold was fabricated using the electrospinning method and its nanotopography and porous structure were characterized using scanning electron microscopy. In addition, the attachment of hAd-MSCs on the PCL/PLA scaffolds was semiquantitatively investigated. Compared with other treatments, the PCL/PLA nanofibrous scaffold supplemented with both 5-azacytidine and TGF-β was observed to differentiate hAd-MSCs into cardiomyocytes at Day 21 as evidenced by real-time PCR for cardiac-specific genes including cardiac troponin I (cTnI), GATA4, MYH7, and NKX2.5. In addition, flow cytometric analysis of cTnI-positive cells demonstrated that the cardiomyocyte differentiation of hAd-MSCs was more efficient on the PCL/PLA nanofibrous scaffold supplemented with both 5-azacytidine and TGF-β than it was in the other treatment groups. Generally speaking, the results show that PCL/PLA nanofibrous scaffolds may be applied as a platform for efficient differentiation of hAd-MSCs into functional cardiomyocytes.

lncRNA FGD5-AS1 Regulates Bone Marrow Stem Cell Proliferation and Apoptosis by Affecting miR-296-5p/STAT3 Axis in Steroid-Induced Osteonecrosis of the Femoral Head

Background

Osteonecrosis of the femoral head (ONFH) is a common hip joint disease, which is more harmful and seriously affects the lives of patients. This study aims to clarify the regulatory mechanism of lncRNA FGD5-AS1 in ONFH.

Methods

The expression of the protein and mRNA was detected by RT-qPCR and Western blot assay. The regulatory mechanism of lncRNA FGD5-AS1 was detected by the dual-luciferase reporter assay, CCK-8 assay, and flow cytometry assay.

Results

Dex can inhibit cell proliferation and differentiation and induce apoptosis in hBMSCs in a dose-dependent manner. Overexpression of lncRNA FGD5-AS1 promoted cell proliferation and restrained apoptosis in Dex-treated hBMSCs. In addition, lncRNA FGD5-AS1 acts as a sponge for miR-296-5p. Also, miR-296-5p directly targets STAT3. More importantly, miR-296-5p and STAT3 can affect the function of lncRNA FGD5-AS1 in Dex-treated hBMSCs.

Conclusion

lncRNA FGD5-AS1 promotes cell proliferation and inhibits apoptosis in steroid-induced ONFH through acting as a sponge for miR-296-5p and upregulation of STAT3.

The effect of shear stress on cardiac differentiation of mesenchymal stem cells

BACKGROUND

Stem cell therapy is developing as a valuable therapeutic trend for heart diseases. Most recent studies are aimed to find the most appropriate types of stem cells for the treatment of myocardial infarction (MI). The animal models have shown that bone marrow-derived mesenchymal stem cells (BMSCs) are a possible, safe, and efficient type of stem cell used in MI. The previous study demonstrated that 5-Azacytidine (5-Aza) could promote cardiac differentiation in stem cells.

METHODS

This study used 5-Aza to induce cardiomyocyte differentiation in BMSCs both in static and microfluidic cell culture systems. For this purpose, we investigated the differentiation by using real-time PCR and Immunocytochemistry (ICC) Analysis.

RESULTS

Our results showed that 5-Aza could cause to express cardiac markers in BMSCs as indicated by real-time PCR and immunocytochemistry (ICC). However, BMSCs are exposed to both 5-Aza and shear stress, and their synergistic effects could significantly induce cardiac gene expressions in BMSCs. This level of gene expression was observed neither in 5-Aza nor in shear stress groups only.

CONCLUSIONS

These results demonstrate that when BMSCs expose to 5-Aza as well as mechanical cues such as shear stress, the cardiac gene expression can be increased dramatically.

Assessment of electromechanically stimulated bone marrow stem cells seeded acellular cardiac patch in a rat myocardial infarct model

In this study, we evaluated cardiomyogenic differentiation of electromechanically stimulated rat bone marrow-derived stem cells (rt-BMSCs) on an acellular bovine pericardium (aBP) and we looked at the functioning of this engineered patch in a rat myocardial infarct (MI) model. aBP was prepared using a detergent-based decellularization procedure followed by rt-BMSCs seeding, and electrical, mechanical, or electromechanical stimulations (3 millisecond pulses of 5 V cm^-1at 1 Hz, 5% stretching) to enhance cardiomyogenic differentiation. Furthermore, the electromechanically stimulated patch was applied to the MI region over 3 weeks. After this period, the retrieved patch and infarct region were evaluated for the presence of calcification, inflammatory reaction (CD68), patch to host tissue cell migration, and structural sarcomere protein expressions. In conjunction with any sign of calcification, a higher number of BrdU-labelled cells, and a low level of CD68 positive cells were observed in the infarct region under electromechanically stimulated conditions compared with static conditions. More importantly, MHC, SAC, Troponin T, and N-cad positive cells were observed in both infarct region, and retrieved engineered patch after 3 weeks. In a clear alignment with other results, our developed acellular patch promoted the expression of cardiomyogenic differentiation factors under electromechanical stimulation. Our engineered patch showed a successful integration with the host tissue followed by the cell migration to the infarct region.

Cardiac Differentiation of Mesenchymal Stem Cells: Impact of Biological and Chemical Inducers

Cardiovascular disorders (CVDs) are the leading cause of global death, widely occurs due to irreparable loss of the functional cardiomyocytes. Stem cell-based therapeutic approaches, particularly the use of Mesenchymal Stem Cells (MSCs) is an emerging strategy to regenerate myocardium and thereby improving the cardiac function after myocardial infarction (MI). Most of the current approaches often employ the use of various biological and chemical factors as cues to trigger and modulate the differentiation of MSCs into the cardiac lineage. However, the recent advanced methods of using specific epigenetic modifiers and exosomes to manipulate the epigenome and molecular pathways of MSCs to modify the cardiac gene expression yield better profiled cardiomyocyte like cells in vitro. Hitherto, the role of cardiac specific inducers triggering cardiac differentiation at the cellular and molecular level is not well understood. Therefore, the current review highlights the impact and recent trends in employing biological and chemical inducers on cardiac differentiation of MSCs. Thereby, deciphering the interactions between the cellular microenvironment and the cardiac inducers will help us to understand cardiomyogenesis of MSCs. Additionally, the review also provides an insight on skeptical roles of the cell free biological factors and extracellular scaffold assisted mode for manipulation of native and transplanted stem cells towards translational cardiac research.

Cardio Phenotypic Potential of Mesenchymal Stem Cells

Cell therapy is being investigated as a powerful intervention to ameliorate the consequences of coronary artery disease. Among the different stem cell options, mesenchymal stem cells (MSCs) are particularly attractive due to their high availability, as well as immune-privileged status. However, it is still unclear whether mesenchymal stem cells can acquire cardiomyogenic characteristics after they are transplanted to the myocardium. In this article, we outline protocols that illustrate the plasticity of MSCs and their ability to acquire cardiogenic characteristics when they are in an ischemic-like environment, as typically encountered after transplantation into the ischemic heart. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Isolation of mesenchymal stem cells (MSCs) Support Protocol 1: Characterization of MSCs by flow cytometry Basic Protocol 2: Isolation of neonatal cardiomyoctes (NCMs) Support Protocol 2: Characterization of NCMs Basic Protocol 3: Cardiogenic plasticity of MSCs under ischemic-like conditions Support Protocol 3: Characterization of the cardiomyogenic potential of MSCs.

SETD4 in the Proliferation, Migration, Angiogenesis, Myogenic Differentiation and Genomic Methylation of Bone Marrow Mesenchymal Stem Cells

Epigenetic modification is a crucial mechanism affecting the biological function of stem cells. SETD4 is a histone methyltransferase, and its biological role in bone marrow mesenchymal stem cells (BMSCs) is currently unknown. In this study, we employed CRISPR/Cas9 technology edited mouse model and found that SETD4 knockout significantly promoted the proliferation of BMSCs, impaired BMSCs migration and differentiation potentials of lineages of cardiacmyocyte and smooth muscle cell, and even the angiogenesis via paracrine of VEGF. Through Reduced Representation Bisulfite Sequencing (RRBS) method, we verified that the overall genomic methylation of BMSCs in the SETD4 knockout group only was decreased by 0.47 % compared with wild type. However, the changed genomic methylation covers a total of 96,331 differential methylated CpG sites and 8,692 differential methylation regions (DMRs), with part of them settled in promoter regions. Bioinformatic analysis revealed that differential CpG islands and DMRs in promoter impacted 270 GO functions and 34 KEGG signaling pathways, with some closely related to stem cell biology. Mechanismly, SETD4 knockout inhibited sets of monomethylases and dimethylases for histone lysine, along with significant changes in some factors including Nkx2.5, Gata4, Gli2, Grem2, E2f7, Map7, Nr2f2 and Shox2 that associated with stem cell biology. These results are the first to reveal that even though SETD4 changes the genome's overall methylation to a limited extent in BMSCs, it still affects the numerous cellular functions and signaling pathways, implying SETD4-altered genomic methylation serves a crucial molecular role in BMSCs' biological functions.

LncRNA NORAD promotes bone marrow stem cell differentiation and proliferation by targeting miR-26a-5p in steroid-induced osteonecrosis of the femoral head

BACKGROUND

Steroid-induced osteonecrosis of the femoral head (SONFH) is a devastating orthopedic disease, which seriously affects the quality of life of patients. The study aims to investigate the effects of LncRNA NORAD on SONFH.

METHODS

Human bone marrow-derived mesenchymal stem cells (hBMSCs) were isolated from the proximal femur of patients during routine orthopedic surgery and then cultured with dexamethasone (Dex) and transfected with NORAD overexpression vector, siRNA-NORAD and miR-26a-5p mimics. The mRNA expression of NORAD, miR-26a-5p, OPG, RANK, and RANKL was detected by RT-qPCR. Cell proliferation and apoptosis was measured by CCK-8 assay and flow cytometry, respectively. The protein expression of RUNX2, OPG, RANK, and RANKL was detected by western blot. The dual-luciferase reporter gene assay was performed to confirm the binding between NORAD and miR-26a-5p.

RESULTS

NORAD expression was downregulated in SONFH tissues, while miR-26a-5p expression was upregulated. Overexpression of NORAD improved DEX-induced inhibition of proliferation and differentiation, and promotion of apoptosis in hBMSCs, while knockdown of NORAD led to the opposite results. Moreover, NORAD improved DEX-induced inhibition of proliferation and differentiation, and promotion of apoptosis by regulation of miR-26a-5p in hBMSCs.

CONCLUSIONS

NORAD expression was downregulated in SONFH tissues, while miR-26a-5p expression was upregulated. NORAD improved DEX-induced inhibition of proliferation and differentiation, and promotion of apoptosis by regulation of miR-26a-5p in hBMSCs.

In vitro differentiation of W8B2+ human cardiac stem cells: gene expression of ionic channels and spontaneous calcium activity

Background

Human cardiac stem cells expressing the W8B2 marker (W8B2⁺ CSCs) were recently identified and proposed as a new model of multipotent CSCs capable of differentiating into smooth muscle cells, endothelial cells and immature myocytes. Nevertheless, no characterization of ion channel or calcium activity during the differentiation of these stem cells has been reported.

Methods

The objectives of this study were thus to analyze (using the TaqMan Low-Density Array technique) the gene profile of W8B2⁺ CSCs pertaining to the regulation of ion channels, transporters and other players involved in the calcium homeostasis of these cells. We also analyzed spontaneous calcium activity (via the GCaMP calcium probe) during the in vitro differentiation of W8B2⁺ CSCs into cardiac myocytes.

Results

Our results show an entirely different electrophysiological genomic profile between W8B2⁺ CSCs before and after differentiation. Some specific nodal genes, such as Tbx3, HCN, ICaT, L, KV, and NCX, are overexpressed after this differentiation. In addition, we reveal spontaneous calcium activity or a calcium clock whose kinetics change during the differentiation process. A pharmacological study carried out on differentiated W8B2⁺ CSCs showed that the NCX exchanger and IP3 stores play a fundamental role in the generation of these calcium oscillations.

Conclusions

Taken together, the present results provide important information on ion channel expression and intrinsic calcium dynamics during the differentiation process of stem cells expressing the W8B2 marker.

Gap Junction Dependent Cell Communication Is Modulated During Transdifferentiation of Mesenchymal Stem/Stromal Cells Towards Neuron-Like Cells

In vitro transdifferentiation of patient-derived mesenchymal stem/stromal cells (MSCs) into neurons is of special interest for treatment of neurodegenerative diseases. Although there are encouraging studies, little is known about physiological modulations during this transdifferentiation process. Here, we focus on the analysis of gap junction dependent cell-cell communication and the expression pattern of gap junction-building connexins during small molecule-induced neuronal transdifferentiation of human bone marrow-derived MSCs. During this process, the MSC markers CD73, CD90, CD105, and CD166 were downregulated while the neuronal marker Tuj1 was upregulated. Moreover, the differentiation protocol used in the present study changed the cellular morphology and physiology. The MSCs evolved from a fibroblastoid morphology towards a neuronal shape with round cell bodies and neurite-like processes. Moreover, depolarization evoked action potentials in the transdifferentiated cells. MSCs expressed mRNAs encoding Cx43 and Cx45 as well as trace levels of Cx26, Cx37- and Cx40 and allowed transfer of microinjected Lucifer yellow. The differentiation protocol increased levels of Cx26 (mRNA and protein) and decreased Cx43 (mRNA and protein) while reducing the dye transfer. Cx36 mRNA was nearly undetectable in all cells regardless of treatment. Treatment of the cells with the gap junction coupling inhibitor carbenoxolone (CBX) only modestly altered connexin mRNA levels and had little effect on neuronal differentiation. Our study indicates that the small molecule-based differentiation protocol generates immature neuron-like cells from MSCs. This might be potentially interesting for elucidating physiological modifications and mechanisms in MSCs during the initial steps of differentiation towards a neuronal lineage.

Direct Conversion of Human Dermal Fibroblasts into Cardiomyocyte-Like Cells Using CiCMC Nanogels Coupled with Cardiac Transcription Factors and a Nucleoside Drug

Using direct conversion technology, normal adult somatic cells can be routinely switched from their original cell type into specific differentiated cell types by inducing the expression of differentiation-related transcription factors. In this study, normal human dermal fibroblasts (NHDFs) are directly converted into cardiomyocyte-like cells by drug and gene delivery using carboxymethylcellulose (CMC) nanoparticles (CiCMC-NPs). CMC-based multifunctional nanogels containing specific cardiomyocyte-related genes are designed and fabricated, including GATA4, MEF2C, and TBX5 (GMT). However, GMT alone is insufficient, at least in vitro, in human fibroblasts. Hence, to inhibit proliferation and to induce differentiation, 5-azacytidine (5-AZA) is conjugated to the hydroxyl group of CMC in CiCMC-NPs containing GMT; in addition, the CMC is coated with polyethylenimine. It is confirmed that the CiCMC-NPs have nanogel properties, and that they exhibit the characteristic effects of 5-AZA and GMT. When CiCMC-NPs-containing 5-AZA and GMT are introduced into NHDFs, cardiomyocyte differentiation is initiated. In the reprogrammed cells, the mature cardiac-specific markers cardiac troponin I and α-actinin are expressed at twofold to threefold higher levels than in NHDFs. Engineered cells transplanted into live hearts exhibit active pumping ability within 1 day. Histology and immunohistology of heart tissue confirm the presence of transplanted engineered NHDF cells at injection sites.

RNA-Based Strategies for Cardiac Reprogramming of Human Mesenchymal Stromal Cells

Multipotent adult mesenchymal stromal cells (MSCs) could represent an elegant source for the generation of patient-specific cardiomyocytes needed for regenerative medicine, cardiovascular research, and pharmacological studies. However, the differentiation of adult MSC into a cardiac lineage is challenging compared to embryonic stem cells or induced pluripotent stem cells. Here we used non-integrative methods, including microRNA and mRNA, for cardiac reprogramming of adult MSC derived from bone marrow, dental follicle, and adipose tissue. We found that MSC derived from adipose tissue can partly be reprogrammed into the cardiac lineage by transient overexpression of GATA4, TBX5, MEF2C, and MESP1, while cells isolated from bone marrow, and dental follicle exhibit only weak reprogramming efficiency. qRT-PCR and transcriptomic analysis revealed activation of a cardiac-specific gene program and up-regulation of genes known to promote cardiac development. Although we did not observe the formation of fully mature cardiomyocytes, our data suggests that adult MSC have the capability to acquire a cardiac-like phenotype when treated with mRNA coding for transcription factors that regulate heart development. Yet, further optimization of the reprogramming process is mandatory to increase the reprogramming efficiency.

miRNA‑15a‑5p facilitates the bone marrow stem cell apoptosis of femoral head necrosis through the Wnt/β‑catenin/PPARγ signaling pathway

Bone marrow stem cells (BMSCs) are a group cells that function as an underlying cell source for bone tissue regeneration. However, the molecular mechanisms of how BMSCs are induced into apoptosis remains unclear. In the present study, it was demonstrated that the molecular mechanisms of BMSCs were exerted via microRNA-15a-5p (miR-15a-5p) in femoral head necrosis (FHN). Briefly, miRNA-15a-5p expression was elevated in a rat model of FHN. Overexpression of miR-15a-5p promoted the apoptosis of BMSCs and reduced cell growth through the Wnt/β-catenin/peroxisome proliferator-activated receptor γ (PPARγ) signaling pathway. Downregulation of miR-15a-5p reduced the apoptosis of BMSCs and promoted cell growth through the Wnt/β-catenin/PPARγ signaling pathway. The activation of Wnt attenuated the effects of miR-15a-5p on the apoptosis of BMSCs via the β-catenin/PPARγ signaling pathway. In conclusion, the present results indicated that miRNA-15a-5p was involved in the regulation of the apoptosis of BMSCs through regulating the Wnt/β-catenin/PPARγ signaling pathway, which may serve an important role in the regulation of FHN.

Differentiation of brown adipose-derived stem cells into cardiomyocyte-like cells is regulated by a combination of low 5-azacytidine concentration and bone morphogenetic protein 4

Adipose-derived stem cells (ADSCs) could be an ideal candidate for seed cells to regenerate damaged heart tissue. This study examined and compared the cardio-myogenic differentiation efficacy of neonatal rat brown ADSCs (rbADSCs) treated with either 5-azacytidine (5-AZA), bone morphogenetic protein 4 (BMP4), or lower doses of both molecules. Briefly, by investigating the protein expression of cardiac-specific markers (i.e., cardiac troponin-I, α-sarcomeric actinin, sarcoplasmic reticulum Ca²⁺-ATPase, and connexin 43), our data indicated that rbADSCs could be differentiated into cardiomyocyte-like cells by all three treatments. By quantitatively measuring the number of cells with positive staining for the above markers, we found that the low-dose combined treatment showed higher differentiation efficiency compared to standard dose 5-AZA and BMP4 treatment. Similarly, the expression levels of these proteins as determined by western blotting were higher in the low-dose combination group than in the standard dose 5-AZA and BMP4 groups. Also, the combined strategy maintained the decreased cell viability caused by cytotoxicity of 5-AZA, probably through reducing the ratio of apoptotic rbADSCs. Furthermore, the extracellular regulated protein kinase (ERK) signaling pathways participate in the differentiation process, but the observed effects between the BMP4 and 5-Aza treatments are quite different.

The cardiac niche role in cardiomyocyte differentiation of rat bone marrow-derived stromal cells: comparison between static and microfluidic cell culture methods

Due to the restricted potential of the heart to regenerate its damaged region, stem cell therapy is a promising treatment modality for myocardial infarction. It has been shown that incubation of bone marrow-derived stromal cells (BMSCs) with initial steps of cardiac differentiation in vitro, can have a significant effect on their therapeutic potential to treat myocardial infarction. Based on these well-established principals we were encouraged to study the direct co-culture of rat BMSCs with neonatal mouse almost pure cardiomyocytes (APCs) and cardiac niche cells (CNCs) in static 2D and microfluidic cell culture systems. Our results showed that the difference regarding the beating rate in isolated APCs and CNCs in both 2D and the microfluidic system was not statistically significant for 30 days. No beat rate could be observed in induced BMSCs in all groups during experiment time. Except for BMSCs cultured alone in both experimental culture conditions, data obtained from Real-time PCR analysis showed that differentiated BMSCs in all co-cultured groups expressed GATA4, Nkx2.5, CX43, cTnI, cTnT, and β-MHC during 4 weeks. BMSCs demonstrated a higher expression of these cardiac factors in microfluidic chips than those co-cultured in 24 well plates. Moreover, immunocytochemistry (ICC), also revealed the GATA4 expression in differentiated BMSCs in all co-cultured groups. It was found that, when combined with shear stress, co-culture with cardiomyocyte can differentiate BMSCs significantly toward cardiomyocyte rather than co-culture alone.

CD105+ Porcine Endometrial Stromal Mesenchymal Stem Cells Possess Differentiation Potential Toward Cardiomyocyte-Like Cells and Insulin-Producing β Cell-Like Cells In Vitro

Porcine mesenchymal stem cells (MSCs) are similar to human MSCs, hence considered a valuable model for assessing potential for cell therapy. Porcine adipose-derived MSCs (AD-MSCs) and endometrial stromal MSCs (EMSCs) displayed fibroblast-like morphology and were positive for MSC markers CD73, CD90, and CD105 and negative for hematopoietic markers CD34 and CD45. The EMSCs had similar or slightly higher growth rate compared to AD-MSCs, and similar percentage of cells of both EMSCs and AD-MSCs were at G0/G1 and G2/M phases; however, EMSCs had significantly ( P < .05) higher percentage of cells at S phase of cell cycle than AD-MSCs. Transdifferentiation ability to cardiomyocyte-like cells was confirmed in differentiated cells by the expression of lineage-specific marker genes such as DES, ACTA2, cTnT, and ACTC1 by real-time quantitative polymerase chain reaction (RT-qPCR). Furthermore, cardiomyocyte-specific protein markers cTnT and ACTC1 were expressed in completely differentiated cells. Endodermal differentiation capacity of EMSCs to pancreatic β cell-like cells was evident with the changes in morphology and the expression of β-cell-specific marker genes such as PDX1, GLUT2, SST, NKX6.1, PAX4, and NGN3 as analyzed by RT-qPCR. The differentiated cells secreted insulin and C-peptide upon glucose challenge and also they expressed insulin, PDX1, PAX4, NGN3, and GLUT2 at protein level as assessed by immunostaining confirming the successful differentiation to β cell-like cells. Porcine EMSCs possess all the characteristics of MSCs and are suitable model for studying molecular mechanisms of cellular differentiation.

Comparative Study on In Vitro Culture of Mouse Bone Marrow Mesenchymal Stem Cells

In vitro culture of mesenchymal stem cells (MSCs) from mouse bone marrow (BM) has been hampered because of the low yield of MSCs during isolation and the contamination of hematopoietic cells during expansion. The lack of specific mouse BM-MSC markers increases the difficulty. Several techniques have been reported to improve the purity and in vitro growth of mouse BM-MSCs. However, systematic report on comparison of characteristics in primary BM-MSCs between different culture conditions is rare. Here, we studied the effects of oxygen concentrations and initial medium replacement intervals, along with cell passages, on mouse BM-MSCs isolated with differential adhesion method. BM-MSCs exhibited elevated proliferative and clonogenic abilities in 5% oxygen compared with 10% and 21% oxygen, as well as a better expression of the MSC marker Sca-1. Adipogenic and osteogenetic differentiation of BM-MSCs can be observed in both 21% and 5% oxygen. Adipogenic differentiation appeared stronger under normoxia conditions. BM-MSCs showed increased proliferative capacity and adipogenic/osteogenetic differentiation potential when initial medium replacement interval was 4 days compared with 1 day. As passage number increased, cells were more MSC-like in morphology and in expression of surface markers (positive for CD29, CD44, and Sca-1 and negative for CD11b, CD19, and CD45). These data provide new insight into optimizing the culture method and understanding the biological characteristics of mouse BM-MSCs during in vitro expansion.

MicroRNA-499a-5p Promotes Differentiation of Human Bone Marrow-Derived Mesenchymal Stem Cells to Cardiomyocytes

Since the adult mammalian heart has limited regenerative capacity, cardiac trauma, disease, and aging cause permanent loss of contractile tissue. This has fueled the development of stem cell-based strategies to provide the damaged heart with new cardiomyocytes. Bone marrow-derived mesenchymal stem cells (BM-MSCs) are capable of self-renewal and differentiation into cardiomyocytes, albeit inefficiently. MicroRNAs (miRNAs, miRs) are non-coding RNAs that have the potential to control stem cell fate decisions and are employed in cardiac regeneration and repair. In this study, we tested the hypothesis that overexpression of miR-499a induces cardiomyogenic differentiation in BM-MSCs. Human BM-MSCs (hBM-MSCs) were transduced with lentiviral vectors encoding miR-499a-3p or miR-499a-5p and analyzed by immunostaining and western blotting methods 14 days post-transduction. MiR-499a-5p-transduced cells adopted a polygonal/rod-shaped (myocyte-like) phenotype and showed an increase in the expression of the cardiomyocyte markers α-actinin and cTnI, as cardiogenic differentiation markers. These results indicate that miR-499a-5p overexpression promotes the cardiomyogenic differentiation of hBM-MSCs and may thereby increase their therapeutic efficiency in cardiac regeneration.

Fibrin scaffold could promote survival of the human adipose-derived stem cells during differentiation into cardiomyocyte-like cells

Human adipose-derived stem cells (hADSCs) are capable of differentiation into many cells including cardiac cells. Different types of scaffolds are used for cell differentiation but the best is yet to be determined. In this study, fibrin scaffold (3D) was fabricated using human plasma fibrinogen and compared with culture plates (2D) for the growth and differentiation of hADSCs into cardiomyocyte-like cells. For this purpose, after obtaining the properties of the isolated hADSCs and fibrin scaffold, four biochemical tests were employed to determine the relative growth rate of hADSCs in 2D and 3D cultures. To examine the effects of two different culture systems on cardiomyogenic differentiation, hADSCs were treated with 10 or 50 μM 5-azacytidine (5-Aza) for 24 h and followed until 10 weeks. The results indicated that the growth of hADSCs in 3D significantly increased after the seventh day (P < 0.05). Western blot, qRT-PCR and immunochemistry assays were used to evaluate the rate of cardiac differentiation, which showed significantly higher expression of special cardiac genes such as NKX2.5, Cx43, MLC2v, βMHC, HAND1, HAND2 and cTnI (P < 0.05) in the treated hADSCs with 50 μM 5-Aza in the 3D group. However, the expression level of the specific cardiac proteins in 3D was not significant using western blot and immunofluorescence staining. In conclusion, this study suggests that the fibrin scaffold with a compressive stress of 107.74 kPa can keep the cells alive for 10 weeks and also allows a higher and sooner differentiation of hADSCs into cardiomyocyte-like cells treated with 50 μM 5-Aza.

Recent Progress in Stem Cell Modification for Cardiac Regeneration

During the past decades, stem cell-based therapy has acquired a promising role in regenerative medicine. The application of novel cell therapeutics for the treatment of cardiovascular diseases could potentially achieve the ambitious aim of effective cardiac regeneration. Despite the highly positive results from preclinical studies, data from phase I/II clinical trials are inconsistent and the improvement of cardiac remodeling and heart performance was found to be quite limited. The major issues which cardiac stem cell therapy is facing include inefficient cell delivery to the site of injury, accompanied by low cell retention and weak effectiveness of remaining stem cells in tissue regeneration. According to preclinical and clinical studies, various stem cells (adult stem cells, embryonic stem cells, and induced pluripotent stem cells) represent the most promising cell types so far. Beside the selection of the appropriate cell type, researchers have developed several strategies to produce “second-generation” stem cell products with improved regenerative capacity. Genetic and nongenetic modifications, chemical and physical preconditioning, and the application of biomaterials were found to significantly enhance the regenerative capacity of transplanted stem cells. In this review, we will give an overview of the recent developments in stem cell engineering with the goal to facilitate stem cell delivery and to promote their cardiac regenerative activity.

Stem cell therapies for myocardial infarction in clinical trials: bioengineering and biomaterial aspects

Cardiovascular disease remains the leading cause of death and disability in advanced countries. Stem cell transplantation has emerged as a promising therapeutic strategy for acute and chronic ischemic cardiomyopathy. The current status of stem cell therapies for patients with myocardial infarction is discussed from a bioengineering and biomaterial perspective in this review. We describe (a) the current status of clinical trials of human pluripotent stem cells (hPSCs) compared with clinical trials of human adult or fetal stem cells, (b) the gap between fundamental research and application of human stem cells, (c) the use of biomaterials in clinical and pre-clinical studies of stem cells, and finally (d) trends in bioengineering to promote stem cell therapies for patients with myocardial infarction. We explain why the number of clinical trials using hPSCs is so limited compared with clinical trials using human adult and fetal stem cells such as bone marrow-derived stem cells.

Oxidized low-density lipoprotein (ox-LDL) promotes cardiac differentiation of bone marrow mesenchymal stem cells via activating ERK1/2 signaling

BACKGROUND/AIMS

The differentiation efficiency of bone marrow mesenchymal stem cells (BM-MSCs) is low in vivo after transplantation. Therefore, it is necessary to look for effective reagents for enhancing cardiac differentiation of BM-MSCs. It has been reported that cardiac differentiation of stem cells depends on the activation of extracellular signal-regulated protein 1/2 (ERK1/2) signaling. Oxidized low-density lipoprotein (ox-LDL) is a potent reagent for ERK1/2 activation. This indicates that ox-LDL may be a potential reagent to stimulate cardiac differentiation of stem cells. In this study, we investigated the effect of ox-LDL on cardiac differentiation of BM-MSCs and its relationship with ERK1/2 signaling.

METHODS

BM-MSCs were isolated from mouse bone marrow, cultured in DMEM supplemented with 15% FBS, and passaged up to the 3rd passage. Following culture with 5 μg/mL ox-LDL for 3 weeks, the cardiac differentiation of the 3rd passage BM-MSCs was identified by immunostaining, Western blotting, and RT-PCR assays for measuring the expression of cardiac-specific markers. To further explore the role of ERK1/2 signaling in cardiac differentiation of BM-MSCs, we simultaneously exposed BM-MSCs to ERK1/2 inhibitor (U0126) and ox-LDL, and identified the cardiac differentiation again.

RESULTS

The expressions of cardiac-specific markers including α-cardiac actin, α-MHC, β-MHC, ANP, and BNP were markedly increased in BM-MSCs following treatment with ox-LDL (P < .05), which indicates a directional differentiation of BM-MSCs to cardiac cells. Further, ox-LDL could also activate ERK1/2 in BM-MSCs, and application of U0126 markedly inhibited ox-LDL-induced cardiac transformation of BM-MSCs.

CONCLUSIONS

Ox-LDL induces cardiac differentiation of BM-MSCs via activation of ERK1/2 signaling.

A comparative study of the influence of two types of PHEMA stents on the differentiation of ASCs to myocardial cells

In the present study, subcutaneous fat was obtained from adult women that had undergone conventional liposuction surgery. A comparative study was performed to investigate the effect of transparent and white poly-β-hydroxyethyl methacrylate (PHEMA) stents, which have different surface and cross-sectional morphological characteristics, on the differentiation of adipose-derived stem cells (ASCs) into myocardial cells. The cell counting kit-8 assay revealed that cell growth increased at varying rates among the different treatment groups. The absorbance of the experimental transparent PHEMA treated group increased in a time-dependent manner with the duration of incubation. The highest levels of proliferation were observed in the transparent PHEMA group. In addition, the transparent PHEMA treated group exhibited the strongest cell adhesion ability, which was significantly different to that of the white PHEMA group (P<0.01 and P<0.05 for Matrigel and fibronectin assay, respectively). Comparisons between the two stent materials with the inducer control group revealed statistically significant differences in the rate of ASC differentiation (P<0.05). The level of differentiation was the greatest in the transparent PHEMA group, and was significantly different to the white PHEMA group (P<0.05) and the blank control group (P<0.01). The results suggest that the inducers 5-aza-2-deoxycytidin and laminin, and material microstructure stents effectively promote the proliferation, growth and adhesion of ASCs. However, the transparent material microstructure may be a more suitable candidate for ASC-associated injections. The present study provides further evidence that a PHEMA stent structure, comprised of a high number of matrixes and a low water content, induces a high level of ASC differentiation to myocardial cells.

Protective Effect of 17β-Estradiol Upon Hippocampal Spine Density and Cognitive Function in an Animal Model of Vascular Dementia

The current study examined whether the steroid hormone, 17β-estradiol (E2) can exert long-lasting beneficial effects upon axonal health, synaptic plasticity, dementia-related amyloid-beta (Aβ) protein expression, and hippocampal-dependent cognitive function in an animal model of chronic cerebral hypoperfusion and vascular dementia (VaD). Chronic cerebral hypoperfusion and VaD was induced by bilateral common carotid artery occlusion (BCCAO) in adult male Sprague Dawley rats. Low dose E2 administered for the first 3-months after BCCAO exerted long-lasting beneficial effects, including significant neuroprotection of hippocampal CA1 neurons and preservation of hippocampal-dependent cognitive function when examined at 6-months after BCCAO. E2 treatment also prevented BCCAO-induced damage to hippocampal myelin sheaths and oligodendrocytes, enhanced expression of the synaptic proteins synaptophysin and PSD95 in the hippocampus, and prevented BCCAO-induced loss of total and mushroom dendritic spines in the hippocampal CA1 region. Furthermore, E2-treatment also reduced BCCAO induction of dementia-related proteins expression such as p-tau (PHF1), total ubiquitin, and Aβ1-42, when examined at 6 m after BCCAO. Taken as a whole, the results suggest that low-dose E2 replacement might be a potentially promising therapeutic modality to attenuate or block negative neurological consequences of chronic cerebral hypoperfusion and VaD.