Effect of valproic acid on the hepatic differentiation of mesenchymal stem cells in 2D and 3D microenvironments

Preconditioning of Human Umbilical Cord Mesenchymal Stem Cells with a Histone Deacetylase Inhibitor: Valproic Acid

Background

Mesenchymal stem cells (MSCs) play a key role in regenerative medicine due to their capacity to differentiate into multiple cell lines, regulate the immune system, and exert paracrine effects. The therapeutic impact of MSCs is primarily mediated through their secretome. The secretory and therapeutic potential of MSCs can be improved through preconditioning, which entails the application of hypoxic environments, 3-dimensional cell cultures, and pharmacological agents. Valproic acid (VPA) is a histone deacetylase inhibitor that is employed in medical practice for treating epilepsy and bipolar disorder. Hence, preconditioning MSCs with VPA is expected to induce histone acetylation, enhance gene expression, and beneficially modify the cells' secretomes.

Aims

To assess the effectiveness of VPA in enhancing and regulating the therapeutic potential of cells as well as its impact on MSC secretome profiles and ultrastructural morphologies.

Study Design

Expiremental study.

Methods

Human umbilical cord MSCs were preconditioned with 2 mM VPA for 24 and 48 hours; untreated MSCs served as controls. The secretome secreted by the cells was assessed for its total protein content. Subsequently, interferon-gamma (IFN-γ), interleukin-17 (IL-17), IL-10, vascular endothelial growth factor, nerve growth factor (NGF), glial cell line-derived neurotrophic factor, and brain-derived neurotrophic factor (BDNF) levels in the secretome were analyzed using the ELISA method. The ultrastructural properties of the cells were studied under transmission electron microscopy.

Results

Ultrastructural examinations revealed that the chromatin content of VPA-treated cells was reduced. VPA-preconditioned cells exhibited a higher density of rough endoplasmic reticulum, autophagic vesicles, and myelin figures on cytoplasmic structure analysis, which was indicative of increased secretion. Protein secretion was elevated in those cells, with notable increases in NGF and BDNF levels. Furthermore, the cytoskeletal rearrangement and elevated autophagic activity observed in the 48-hour preconditioned cells could indicate the initiation of neuronal differentiation. IL-10, IL-17, and IFN-γ were not detected in the secretome.

Conclusion

This study indicate that preconditioning with VPA enhances MSC activity and subsequently modifies the secretome content.

Novel Chitosan-Gelatin Scaffold with Valproic Acid Augments In Vitro Osteoblast Differentiation of Mesenchymal Stem Cells

The study aimed to develop a biodegradable scaffold incorporating valproic acid (VPA) for improved human bone marrow-derived mesenchymal stem cell (hBMSC) proliferation, differentiation, and bone mineral synthesis. A chitosan-gelatin (CH-G) scaffold was fabricated and loaded with varying concentrations of VPA (1, 3, 5 mM/L). In vitro studies assessed drug release, cell proliferation, morphology, mineralization, and gene expression. VPA was rapidly released from the scaffold, with over 90% cumulative release within seven days. Cells cultured on VPA-loaded scaffolds exhibited significantly enhanced proliferation and mineralization compared to the control. VPA treatment upregulated osteocalcin and runt-related transcription factor 2 (Runx-2) expression, key markers of osteogenic differentiation. The CH-G scaffold, particularly with 1 mM/L VPA, demonstrates excellent biocompatibility and promotes hBMSC-mediated bone regeneration. This novel approach holds promise for future applications in bone tissue engineering.

HDAC inhibitors support long-term expansion of porcine hepatocytes in vitro

Hepatocyte transplantation is an effective treatment for end-stage liver disease. However, due to the limited supply of human hepatocytes, porcine hepatocytes have garnered attention as a potential alternative source. Nonetheless, traditional primary porcine hepatocytes exhibit certain limitations in function maintenance and in vitro proliferation. This study has discovered that by using histone deacetylase inhibitors (HDACi), primary porcine hepatocytes can be successfully reprogrammed into liver progenitor cells with high proliferative potential. This method enables porcine hepatocytes to proliferate over an extended period in vitro and exhibit increased susceptibility in lentivirus-mediated gene modification. These liver progenitor cells can readily differentiate into mature hepatocytes and, upon microencapsulation transplantation into mice with acute liver failure, significantly improve the survival rate. This research provides new possibilities for the application of porcine hepatocytes in the treatment of end-stage liver disease.

Chemical Hypoxic Preconditioning Improves Survival and Proliferation of Mesenchymal Stem Cells

Increasing evidence has demonstrated that mesenchymal stem cells (MSCs) have been linked to tissue regeneration both in vitro and in vivo. However, poor engraftment and low survival rate of transplanted MSCs are still a major concern. It has been found that the proliferation, survival, and migration of MSCs are all increased by hypoxic preconditioning. However, the molecular mechanism through which hypoxic preconditioning enhances these beneficial properties of MSCs remains to be fully investigated. Therefore, the present study is aimed to investigate the mechanism by which hypoxic preconditioning enhances the survival of MSCs. We used proteomic analysis to explore the molecules that may contribute to the survival and proliferation of hypoxic preconditioned (HP) MSCs. The analysis revealed a higher expression of prelamin A/C (Lmna), glutamate dehydrogenase 1(Glud1), Actin, cytoplasmic 1(Actb), Alpha-enolase (Eno1), Glucose-6-phosphate 1-dehydrogenase (G6pd), Protein disulfide-isomerase A3 (Pdia3), Malate dehydrogenase (Mdh1), Peroxiredoxin-6 (Prdx6), Superoxide dismutase (Sod1), and Annexin A2 (Anxa2) in HP-MSCs. These proteins are possibly involved in cellular survival and proliferation through various cellular pathways. This research could aid in understanding the processes involved in hypoxic preconditioning of MSCs and designing of cell-based therapeutic strategies for tissue regeneration.

Ascorbic acid and salvianolic acid B enhance the valproic acid and 5-azacytidinemediated cardiac differentiation of mesenchymal stem cells

BACKGROUND

Cardiovascular diseases remain a major cause of death globally. Cardiac cells once damaged, cannot resume the normal functioning of the heart. Bone marrow derived mesenchymal stem cells (BM-MSCs) have shown the potential to differentiate into cardiac cells. Epigenetic modifications determine cell identity during embryo development via regulation of tissue specific gene expression. The major epigenetic mechanisms that control cell fate and biological functions are DNA methylation and histone modifications. However, epigenetic modifiers alone are not sufficient to generate mature cardiac cells. Various small molecules such as ascorbic acid (AA) and salvianolic acid B (SA) are known for their cardiomyogenic potential. Therefore, this study is aimed to examine the synergistic effects of epigenetic modifiers, valproic acid (VPA) and 5-azacytidine (5-aza) with cardiomyogenic molecules, AA and SA in the cardiac differentiation of MSCs.

METHODS AND RESULTS

BM-MSCs were isolated, propagated, characterized, and then treated with an optimized dose of VPA or 5-aza for 24 h. MSCs were maintained in a medium containing AA and SA for 21 days. All groups were assessed for the expression of cardiac genes and proteins through q-PCR and immunocytochemistry, respectively. Results show that epigenetic modifiers VPA or 5-aza in combination with AA and SA significantly upregulate the expression of cardiac genes MEF2C, Nkx2.5, cMHC, Tbx20, and GATA-4. In addition, VPA or 5-aza pretreatment along with AA and SA enhanced the expression of the cardiac proteins connexin-43, GATA-4, cTnI, and Nkx2.5.

CONCLUSION

These findings suggest that epigenetic modifiers valproic acid and 5-azacytidine in combination with ascorbic acid and salvianolic acid B promote cardiac differentiation of MSCs. This pretreatment strategy can be exploited for designing future stem cell based therapeutic strategies for cardiovascular diseases.

Therapeutic Potential of Mesenchymal Stem Cells in the Treatment of Epilepsy and Their Interaction with Antiseizure Medications

Epilepsy is a life-threatening neurological disease that affects approximately 70 million people worldwide. Although the vast majority of patients may be successfully managed with currently used antiseizure medication (ASM), the search for alternative therapies is still necessary due to pharmacoresistance in about 30% of patients with epilepsy. Here, we review the effects of ASMs on stem cell treatment when they could be, as expected, co-administered. Indeed, it has been reported that ASMs produce significant effects on the differentiation and determination of stem cell fate. In addition, we discuss more recent findings on mesenchymal stem cells (MSCs) in pre-clinical and clinical investigations. In this regard, their ability to differentiate into various cell types, reach damaged tissues and produce and release biologically active molecules with immunomodulatory/anti-inflammatory and regenerative properties make them a high-potential therapeutic tool to address neuroinflammation in different neurological disorders, including epilepsy. Overall, the characteristics of MSCs to be genetically engineered, in order to replace dysfunctional elements with the aim of restoring normal tissue functioning, suggested that these cells could be good candidates for the treatment of epilepsy refractory to ASMs. Further research is required to understand the potential of stem cell treatment in epileptic patients and its interaction with ASMs.

The role of epigenetic modifiers in the hepatic differentiation of human umbilical cord derived mesenchymal stem cells

Human umbilical cord (hUC) derived mesenchymal stem cells (MSCs) can be progressively differentiated into multiple lineages including hepatic lineages, and thus provide an excellent in vitro model system for the study of hepatic differentiation. At present, hepatic differentiation protocols are based on the use of soluble chemicals in the culture medium and provide immature hepatic like cells. Histone deacetylase inhibitors (HDACi) and DNA methyltransferase inhibitors (DNMTi) are two important epigenetic modifiers that regulate stem cell differentiation. Therefore, this study aimed to investigate the role of HDACi, valproic acid (VPA) and DNMTi,5-azacytidine (5-aza) along with a hepatic inducer in the hepatic differentiation of hUC-MSCs. hUC-MSCs were characterized via immunocytochemistry and flow cytometry. The final concentrations of VPA and 5-aza were optimized via MTT cytotoxicity assay. All treated groups were assessed for the presence of hepatic genes and proteins through qPCR and immunocytochemistry, respectively. The results showed that the pretreatment of epigenetic modifiers not only increased the hepatic genes but also increased the expression of the hepatic proteins. VPA induces hepatic differentiation in hUC-MSCs with significant gene expression of hepatic markers i.e., FOXA2 and CK8. Moreover, VPA pretreatment enhanced the expression of hepatic proteins AFP and TAT. The pretreatment of 5-aza shows significant gene expression of hepatic marker LDL-R. However, 5-aza treatment failed to induce hepatic protein expression. The results of the current study highlighted the effectiveness of epigenetic modifiers in the hepatic differentiation of hUC-MSCs. These differentiated cells can be employed in cell-based therapeutics for hepatic diseases in future.

Sodium Butyrate Induces Hepatic Differentiation of Mesenchymal Stem Cells in 3D Collagen Scaffolds

Stem cell-based therapy is considered an attractive tool to overcome the burden of liver diseases. However, efficient hepatic differentiation is still a big challenge for the research community. In this study, we explored a novel method for differentiation of bone marrow-derived mesenchymal stem cells (MSCs) into hepatic-like cells using 3D culture conditions and histone deacetylase inhibitor, sodium butyrate (NaBu). MSCs were characterized by the presence of cell surface markers via immunocytochemistry, flow cytometry, and by their potential for osteogenic, adipogenic, and chondrogenic differentiation. MSCs were treated with 1mM NaBu in 2D and 3D environments for 21 days. The hepatic differentiation was confirmed by qPCR and immunostaining. According to qPCR data, the 3D culture of NaBu-treated MSCs has shown significant upregulation of hepatic gene, CK-18 (P < 0.01), and hepatic proteins, AFP (P < 0.01) and ALB (P < 0.01). In addition, immunocytochemistry analysis showed significant increase (P < 0.05) in the acetylation of histones (H3 and H4) in NaBu-pretreated cells. It can be concluded from the study that NaBu-treated MSCs in 3D culture conditions can induce hepatic differentiation without the use of additional cytokines and growth factors. The method shown in this study represents an improved protocol for hepatic differentiation and could contribute to improvement in future cell-based therapeutics.

Traction of 3D and 4D Printing in the Healthcare Industry: From Drug Delivery and Analysis to Regenerative Medicine

Three-dimensional (3D) printing and 3D bioprinting are promising technologies for a broad range of healthcare applications from frontier regenerative medicine and tissue engineering therapies to pharmaceutical advancements yet must overcome the challenges of biocompatibility and resolution. Through comparison of traditional biofabrication methods with 3D (bio)printing, this review highlights the promise of 3D printing for the production of on-demand, personalized, and complex products that enhance the accessibility, effectiveness, and safety of drug therapies and delivery systems. In addition, this review describes the capacity of 3D bioprinting to fabricate patient-specific tissues and living cell systems (e.g., vascular networks, organs, muscles, and skeletal systems) as well as its applications in the delivery of cells and genes, microfluidics, and organ-on-chip constructs. This review summarizes how tailoring selected parameters (i.e., accurately selecting the appropriate printing method, materials, and printing parameters based on the desired application and behavior) can better facilitate the development of optimized 3D-printed products and how dynamic 4D-printed strategies (printing materials designed to change with time or stimulus) may be deployed to overcome many of the inherent limitations of conventional 3D-printed technologies. Comprehensive insights into a critical perspective of the future of 4D bioprinting, crucial requirements for 4D printing including the programmability of a material, multimaterial printing methods, and precise designs for meticulous transformations or even clinical applications are also given.

Valproic acid promotes the in vitro differentiation of human pluripotent stem cells into spermatogonial stem cell-like cells

Background

Studying human germ cell development and male infertility is heavily relied on mouse models. In vitro differentiation of human pluripotent stem cells into spermatogonial stem cell-like cells (SSCLCs) can be used as a model to study human germ cells and infertility. The current study aimed to develop the SSCLC induction protocol and assess the effects of the developed protocol on SSCLC induction.

Methods

We examined the effects of valproic acid (VPA), vitamin C (VC) and the combination of VPA and VC on the SSCLC induction efficiency and determined the expression of spermatogonial genes of differentiated cells. Haploid cells and cells expressed meiotic genes were also detected. RNA-seq analysis was performed to compare the transcriptome between cells at 0 and 12 days of differentiation and differently expressed genes were confirmed by RT-qPCR. We further evaluated the alteration in histone marks (H3K9ac and H3K27me3) at 12 days of differentiation. Moreover, the SSCLC induction efficiency of two hiPSC lines of non-obstructive azoospermia (NOA) patients was assessed using different induction protocols.

Results

The combination of low concentrations of VPA and VC in the induction medium was most effective to induce SSCLCs expressing several spermatogonial genes from human pluripotent stem cells at 12 days of differentiation. The high concentration of VPA was more effective to induce cells expressing meiotic genes and haploid cells. RNA-seq analysis revealed that the induction of SSCLC involved the upregulated genes in Wnt signaling pathway, and cells at 12 days of differentiation showed increased H3K9ac and decreased H3K27me3. Additionally, two hiPSC lines of NOA patients showed low SSCLC induction efficiency and decreased expression of genes in Wnt signaling pathway.

Conclusions

VPA robustly promoted the differentiation of human pluripotent stem cells into SSCLCs, which involved the upregulated genes in Wnt signaling pathway and epigenetic changes. hiPSCs from NOA patients showed decreased SSCLC induction efficiency and Wnt signaling pathway gene expression, suggesting that SSC depletion in azoospermia testes might be associated with inactivation of Wnt signaling pathway. Our developed SSCLC induction protocol provides a reliable tool and model to study human germ cell development and male infertility.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02621-1.

Human umbilical cord-derived mesenchymal stem cells and their chondroprogenitor derivatives reduced pain and inflammation signaling and promote regeneration in a rat intervertebral disc degeneration model

Intervertebral disc (IVD) degeneration is an asymptomatic pathophysiological condition and a strong causative factor of low back pain. There is no cure available except spinal fusion and pain management. Stem cell-based regenerative medicine is being considered as an alternative approach to treat disc diseases. The current study aimed to differentiate human umbilical cord-mesenchymal stem cells (hUC-MSCs) into chondrocyte-like cells and to elucidate their feasibility and efficacy in the degenerated IVD rat model. Chondrogenic induction medium was used to differentiate hUC-MSCs into chondroprogenitors. Rat tail IVD model was established with three consecutive coccygeal discs. qPCR was performed to quantify the molecular markers of pain and inflammation. Histological staining was performed to evaluate the degree of regeneration. Induced chondroprogenitors showed the expression of chondrogenic genes, SOX9, TGF-β1, ACAN, BMP2, and GDF5. Immunocytochemical staining showed positive expression of chondrogenic proteins SOX9, TGF-β1, TGF-β2, and Collagen 2. In in vivo study, transplanted chondroprogenitors showed better survival, homing, and distribution in IVD as compared to normal MSCs. Expression of pain and inflammatory genes at day 5 of cell transplantation modulated immune response significantly. The transplanted labeled MSCs and induced chondroprogenitors differentiated into functional nucleus pulposus (NP) cells as evident from co-localization of red (DiI) and green fluorescence for SOX9, TGF-β1, and TGF-β2. Alcian blue and H & E staining showed standard histological features, indicating better preservation of the NP structure and cellularity than degenerated discs. hUC-MSCs-derived chondroprogenitors showed better regeneration potential as compared to normal MSCs. The pain and inflammation genes were downregulated in the treated group as compared to the degenerated IVD.