Abstract

Nowadays, it is an established concept that the capability to reach a specialised cell identity via differentiation, as in the case of multi- and pluripotent stem cells, is not only determined by biochemical factors, but that also physical aspects of the microenvironment play a key role; interpreted by the cell through a force-based signalling pathway called mechanotransduction. However, the intricate ties between the elements involved in mechanotransduction, such as the extracellular matrix, the glycocalyx, the cell membrane, Integrin adhesion complexes, Cadherin-mediated cell/cell adhesion, the cytoskeleton, and the nucleus, are still far from being understood in detail. Here we report what is currently known about these elements in general and their specific interplay in the context of multi- and pluripotent stem cells. We furthermore merge this overview to a more comprehensive picture, that aims to cover the whole mechanotransductive pathway from the cell/microenvironment interface to the regulation of the chromatin structure in the nucleus. Ultimately, with this review we outline the current picture of the interplay between mechanotransductive cues and epigenetic regulation and how these processes might contribute to stem cell dynamics and fate.

Introduction

One of the basic principles enabling multicellular life is the differentiation of stem cells (SCs), into specialised cells with a defined identity, shape, and function ( McBeath et al., 2004 ) ( Tewary et al., 2018 ). SCs are defined as cells that are clonogenic, which defines their capability of both, self-renewing and retaining multilineage differentiation potency. In vertebrates, the Zygote represents the earliest stem cell (totipotent) in ontogeny, from which originate the pluripotent stem cells (PSCs) of the inner cell mass of the blastocyst ( Dean et al., 2003 , Smith, 2017 ). Soon thereafter, PSCs continue to expand during embryo development becoming progressively committed in their cell fate and acquiring a more restricted potency ( Dean et al., 2003 , Osorno et al., 2012 , Smith, 2017 ). Even at the end of embryogenesis, when the organism is fully formed, and its organs are composed of functionally mature cells, some SCs are still present. These cells, which possess a more limited differentiating potential (multipotent), in turn, give rise to a progeny of precursor cells and, finally, to functionally mature cells. Some examples are represented by the hematopoietic SCs in the bone marrow, the intestinal SCs in the gut’s crypts, the epithelial SCs in the epidermis or the mesenchymal stem cells (MSCs) which play an important role in the maintenance and regeneration of bones and cartilage ( Barker, 2014 , Evans et al., 2013 , Guan et al., 2012 , Tewary et al., 2018 , Watt, 2002 , Weissman, 2000 ).

The inherent high level of plasticity characterising SCs is at the base of their capability to respond precisely to appropriate stimuli with differentiative behaviour. Understanding this essential principle of multicellular life; i.e., the regulation of cell identity and fate, is one of the most important fields of research in modern cell biology, primarily due to its impact on the development of new therapeutic approaches in regenerative medicine. Such knowledge can directly benefit stem cell bioengineering by leveraging the SC plasticity and control over SC behaviour for the application in tissue engineering, patient-specific disease modelling and cell therapies ( Tewary et al., 2018 ).

Conclusions

In recent years there has been a fascinating expansion of our knowledge about the interplay between mechanotransductive signalling and chromatin regulation, and how this impacts on multi- and pluripotent stem cell dynamics, which we try to highlight in this review.

However, what shapes the life of a cell and its identity, from the outside (biophysical and structural cues of the cellular microenvironment) and from the inside (nuclear and chromatin organisation) and how it is connected (mechanotransduction and epigenetics) are highly relevant biological issues that are yet far from being understood in detail. Starting from the stem cell/microenvironment interface, a much more detailed understanding of the nanoscale events in this interface is necessary to unravel 1) what the SC perceives of the biophysical nature and the 3D adhesion site configuration and 2) how the immanent nanoscale information is interpreted and converted, through force-based actions, into a remodelling at the level of the IACs, cell/cell adhesions, cytoskeleton and nucleus.

Abstract

Liver fibrosis is an intrahepatic chronic damage repair response caused by various reasons such as alcoholic liver, fatty liver, viral hepatitis, autoimmune diseases, etc., and is closely related to the progression of liver disease. Currently, the mechanisms of liver fibrosis and its treatment are hot research topics in the field of liver disease remedy. Mesenchymal stem cells (MSCs) are a class of adult stem cells with self-renewal and multidirectional differentiation potential, which can ameliorate fibrosis through hepatic-directed differentiation, paracrine effects, and immunomodulation. However, the low inner-liver colonization rate, low survival rate, and short duration of intervention after stem cell transplantation have limited their wide clinical application. With the intensive research on liver fibrosis worldwide, it has been found that MSCs and MSCs-derived exosomes combined with drugs have shown better intervention efficiency than utilization of MSCs alone in many animal models of liver fibrosis. In this paper, we review the interventional effects and mechanisms of mesenchymal stem cells and their exosomes combined with drugs to alleviate hepatic fibrosis in vivo in animal models in recent years, which will provide new ideas to improve the efficacy of mesenchymal stem cells and their exosomes in treating hepatic fibrosis in the clinic.

Introduction

The liver is mainly composed of hepatocytes, hepatic stellate cells (HSCs), and liver sinusoidal endothelial cells (LSECs) that perform a comprehensive range of hepatic functions, such as detoxification, bile acid synthesis, and participation in various metabolic processes. However, a variety of stimuli, such as alcohol, drugs, inflammation, or cholestasis, often cause damage to hepatocytes resulting in abnormal liver function and a series of pathophysiologic changes [1] . Liver fibrosis is a common intermediate pathological process of various chronic liver diseases, which is mainly manifested by diffuse excessive deposition of extracellular matrix, leading to abnormal changes in liver tissue structure and affecting the normal physiological functions of liver severely [2] . Clinically, if liver fibrosis is not effectively reversed or curbed, it will progress to irreversible cirrhosis, hepatocellular carcinoma, and other end-stage liver diseases, eventually, leading to the death of patients [3] . Therefore, finding effective therapeutic strategies to ameliorate liver fibrosis in patients is of great importance in preventing the development of end-stage liver diseases.

In the clinical setting, liver transplantation is mostly used for the treatment of end-stage liver diseases, but liver transplantation cannot be widely used due to the defects of extremely rare donors, high cost, rejection, etc [4] . Currently, mesenchymal stem cells for the treatment of liver disease have become a hot spot in the field of biomedicine. As the intermediate pathological process of end-stage liver disease, mesenchymal stem cells can effectively ameliorate hepatic fibrosis through hepatogenic differentiation, immunomodulation, paracrine effects, and other mechanisms [5] . However, it has been reported that MSCs transplanted in the body may have some disadvantages such as low inner-liver colonization and short duration of intervention, which affect their therapeutic efficacy [6] . Nowadays, an increasing number of researchers have demonstrated in animal models of liver fibrosis that the combination of MSCs with drugs can boost the therapeutic effect of MSCs in the treatment of liver fibrosis by promoting the homing of MSCs, differentiating them into functional hepatocyte-like cells, improving the microenvironment, inhibiting the activation of HSCs, and modulating the signaling pathway, and so on. In addition, MSCs-derived extracellular vesicles with the advantages of higher penetrability and lower carcinogenicity also effectively ameliorate liver fibrosis with ultimate safety. What’s more, nanoscale intracellular vesicles can also be used as carriers of natural drugs for drug delivery. This provides new ideas to solve the poor efficiency of MSCs in the treatment of liver fibrosis in the clinic.

Discussion and outlook

Liver fibrosis, as an intermediate pathological process from chronic liver disease to cirrhosis and hepatocellular carcinoma, has become a research hotspot for the treatment of liver diseases due to its reversible properties. However, there is no very effective means to treat liver fibrosis in clinical practice. MSCs, as a kind of pluripotent stem cells, have no ethical issues and wide sources compared with liver transplantation and hepatocyte transplantation, which have attracted much attention in animal experiments and clinical studies of cell transplantation for the treatment of liver fibrosis. Unfortunately, MSCs confront with the challenges such as in vivo microenvironment inadaptation and attenuation of inflammatory response ability after isolation and culture in vitro [45] , which ultimately leads to a low colonization rate and short duration of intervention after transplantation of MSCs into the liver [6] . Therefore, it has not been widely used in clinical practice.

Abstract

Oral cavity stem cells (OCSCs) have been the focus of intense scientific efforts due to their accessibility and stem cell properties. The present work aims to compare the different characteristics of 6 types of dental stem cells derived from the oral cavity: dental pulp stem cells (DPSC), stem cells from human exfoliated deciduous teeth (SHED), periodontal ligament stem cells (PDLSC), stem cells from the apical papilla (SCAP), bone marrow mesenchymal stem cells (BMSC), and gingival mesenchymal stem cells (GMSC). Using immunofluorescence and real-time polymerase chain reaction techniques, we analysed the cells for stem cell, differentiation, adhesion, and extracellular matrix markers; the ability to proliferate in vitro; and multilineage differentiation potential. Markers such as vimentin, CD44, alkaline phosphatase, CD146, CD271, CD49f, Oct 3/4, Sox 9, FGF7, nestin, and BMP4 showed significant differences in expression levels, highlighting the heterogeneity and unique characteristics of each cell type. At the same time, we confirmed that all cell types successfully differentiated into osteogenic, chondrogenic, or adipose lineages, with different readiness. In conclusion, our study reveals the distinct properties and potential applications of various dental-derived stem cells. These findings contribute to a deeper understanding of OCSCs and their significance in future clinical applications.

Introduction

Bone marrow mesenchymal stem cells (BMSCs) exhibit high proliferation ability and multilineage differentiation potential. They were the first mesenchymal stem cells (MSCs) to be described, isolated from adults’ bone marrow aspirate.1 They have been extensively researched in human and animal model systems using in vivo and in vitro cell cultures. Further, they have bridged the divide and are integrated into various trials for clinical applications, with mixed success.2,3 BMSCs are not easily accessible, and an invasive procedure is required. Therefore, further research in the field, aiming at identifying alternative stem cell sources, has led to the discovery of oral cavity stem cells (OCSCs).

Currently, several different types of OCSCs are well known, including dental pulp stem cells (DPSC), stem cells from human exfoliated deciduous teeth (SHED), periodontal ligament stem cells (PDLSC), stem cells from the apical papilla (SCAP), dental follicle stem cells (DFSC), and gingival mesenchymal stem cells (GMSC).

Conclusions

This analysis of oral cavity–derived stem cells has exposed distinct and specific expression patterns of surface markers, ECM components, ECM remodelling enzymes, collagen genes, integrins, and differentiation potential. These findings may provide insights into the functional properties of these cell populations. Оur study aims to uncover the nuanced characteristics specific to each distinct cell type. Through experimentation and analysis, we anticipate to not only understand their individual functionalities but also gain deeper insights into their collective behaviour. Understanding both their shared characteristics and distinct attributes is an important step in using their regenerative potential in various tissue repair and regeneration contexts, thereby advancing the field of regenerative medicine and tissue engineering. By contributing meaningfully to the advancement of knowledge in regenerative medicine and tissue engineering, we aspire to pave the way for transformative breakthroughs in health care.

Abstract

Objective. Mesenchymal stem cell (MSC) therapy has been explored in Huntington disease (HD) as a potential therapeutic approach; however, a complete synthesis of these results is lacking. We conducted a meta-analysis to evaluate the effects of MSCs on HD. Method. Eligible studies published before November 2022 were screened from Embase, PubMed, Web of Science, Medline, and Cochrane in accordance with PRISMA guidelines. ClinicalTrial.gov and the World Health Organization International Clinical Trials Registry Platform were also searched for registered clinical trials. The outcomes in rodent studies evaluated included morphological changes (striatal volume and ventricular volume), motor function (rotarod test, wire hang test, grip strength test, limb-clasping test, apomorphine-induced rotation test, and neuromuscular electromyography activity), cognition (Morris water maze test), and body weight. Result. The initial search returned 362 records, of which 15 studies incorporating 346 HD rodents were eligible for meta-analysis. Larger striatal and smaller ventricular volumes were observed in MSC-treated animals compared to controls. MSCs transplanted before the occurrence of motor dysfunction rescued the motor incoordination of HD. Among different MSC sources, bone marrow mesenchymal stem cells were the most investigated cells and were effective in improving motor coordination. MSC therapy improved muscle strength, neuromuscular electromyography activity, cortex-related motor function, and striatum-related motor function, while cognition was not changed. The body weight of male HD rodents increased after MSC transplantation, while that of females was not affected. Conclusion. Meta-analysis showed a positive effect of MSCs on HD rodents overall, as reflected in morphological changes, motor coordination, muscle strength, neuromuscular electromyography activity, cortex-related motor function, and striatum-related motor function, while cognition was not changed by MSC therapy.

Introduction

Huntington disease (HD) is a neurodegenerative disorder of the central nervous system resulting from a dominantly inherited CAG trinucleotide repeat expansion in exon 1 of the huntingtin (HTT) gene that encodes the Huntingtin protein [1]. Pathological changes are characterized by a general shrinkage of the brain and distinct degeneration of the striatum (caudate nucleus and putamen) [2]. Although HD prevalence is only 4-10 individuals per 100,000, it seriously affects the life quality of the patients in many ways, including movement, cognition, and psychological condition, as well as other functional disabilities [3]. Motor defects typically include chorea and loss of coordination. Psychiatric symptoms, such as depression, psychosis, and obsessive-compulsive disorder, are common in HD [4]. Death typically occurs about 20 years after symptom onset [1].

Current therapies for HD are directed at symptom relief, as there are no any disease-modifying therapies. Therapeutic attempts based on pathogenic mechanisms including gene silencing [5], antiapoptosis/caspase inhibition [6], transglutaminase inhibition [7], antioxidative stress [8], upregulating autophagy [9], and physical exercise [10] have been investigated; unfortunately, none of these have met the criteria for clinical translation. For instance, silencing the expression of the mutant HTT gene is attractive; however, allele specificity and off-target effects are not fully resolved. Treatment of mouse models with antioxidants was considered to be beneficial [8], whereas trials of creatine for symptomatic patients were disappointing [11].

Conclusion

This meta-analysis reveals MSC therapy attenuates morphological changes and improves motor function in HD models, but cognition was not influenced. Furthermore, the weight of male, but not female, HD rodents may be benefited from MSC treatment. These results support MSC-based strategies becoming an alternative treatment for HD; however, before MSC therapies can be translated into clinical practice, their safety, efficacy, and mechanism must be established with more preclinical and clinical studies.

1- Introduction

2- In vitro studies

3- In vivo studies

4- Conclusion(s)

References

Abstract

Stem cell, one of the most exciting research areas of 21st century, is considered to have broaden the horizons of the field of biology, in general and medicine, in particular. Stem cells, owing to their unique characteristics like self-renewal, multiplication and differentiation are considered to provide an ‘all-in-one-solution’ for diverse clinical problems. Among various stem cell types, mesenchymal stem cells (MSCs) are being made the subject of the most of the studies on their therapeutic applications. It is attributable to their readily available sources, ability to immunemodulate and differentiate into mesodermal and extra-mesodermal tissues. MSCs in contrast to pluripotent stem cells carry minimal risk of teratoma formation and are free from any ethical concern. MSCs have been evaluated under innumerable studies but the definitive applications of these cells are slow, plausibly due to the incomplete understanding of their cellular physiology. Goat MSCs (gMSCs) have been isolated, culture expanded, characterized from various tissue sources and studied for their potential in vivo applications mostly in relation to human translational models. The current review throws some light on gMSC sources, characterization and potential therapeutic applications.

Introduction

The stem cells constitute an important element in the discipline of regenerative medicine that aims to address numerous incurable diseases through tissue regeneration (Gugjoo and Amarpal, 2018; Gugjoo et al. 2019). The specialized properties of selfrenewal, multiplication and differentiation of stem cells make them potential candidates for an all-in-one therapeutic solution to diverse clinical ailments. Among various stem cell types, mesenchymal stem cells (MSCs) make subject of most of the therapeutic applications (Gugjoo et al. 2019). MSCs are available in almost all the tissue types and have easy isolation and culture processes. The cells are plastic in nature, and have immunomodulatory and/ anti-inflammatory properties with minimal risk of teratogenicity and associated ethical issues unlike that of embryonic stem cells (Song et al. 2013; Gugjoo et al. 2019).

1- Introduction

2- Development of periodontal tissue

3- Periodontal tissue regeneration with somatic NCCs and MSCs

4- Tissue engineering for periodontal tissue regeneration

5- Periodontal tissue regeneration using pluripotent stem cells

6- Discussion

References

Abstract

Periodontitis is commonly observed and is an important concern in dental health. It is characterized by a multifactorial etiology, including imbalance of oral microbiota, mechanical stress, and systemic diseases such as diabetes mellitus. The current standard treatments for periodontitis include elimination of the microbial pathogen and application of biomaterials for treating bone defects. However, the periodontal tissue regeneration via a process consistent with the natural tissue formation process has not yet been achieved. Developmental biology studies state that periodontal tissue is composed of neural crest-derived ectomesenchyme. To elucidate the process of periodontal regeneration, it is essential to understand the developmental background and intercellular cross-talk. Several recent studies have reported the efficacy of transplantation of mesenchymal stem cells for periodontal tissue regeneration. In this review, we discuss the basic knowledge of periodontal tissue regeneration using mesenchymal stem cells and highlight the potential of stem cell-based periodontal regenerative medicine.

Introduction

Periodontal tissues include soft tissues such as gingiva and periodontal ligaments (PDLs) and hard tissues such as the alveolar bones. Periodontitis is usually defined as bone resorption and periodontal tissue destruction due to acute (sometimes aggressive) or chronic inflammation. And periodontitis is very important concerns not only in dental health but also systemic health. The primary treatments for periodontal tissue inflammation include scaling and root planing and periodontal surgery for periodontal tissue reconstruction. Periodontal tissue regeneration using guided tissue regeneration and enamel matrix derivatives are being used for 2e3-wall alveolar bone defects [1,2]. These methods depend on mesenchymal stem cells (MSCs) residing in the periodontal tissues, space provision for the differentiation of MSCs, and the availability of growth factors.

1- Introduction

2- Mesenchymal stem cells: an overview

3- Engineered MSCs

4- Engineered oncolytic viruses

5- Immune checkpoint inhibitors and oncolytic therapy

6- Non-systemic anticancer therapy with oncolytic virus-loaded MSCs

7- Systemic anticancer therapy with oncolytic virus-loaded MSCs

8- Limitations of MSC use in systemic therapy

9- MSC-mediated oncolytic virotherapy – clinical studies

10- Future directions

References

Abstract 

Progress in genetic engineering led to the emergence of some viruses as potent anticancer therapeutics. These oncolytic viruses combine self-amplification with dual antitumor action: oncolytic (destruction of cancer cells) and immunostimulatory (eliciting acquired antitumor response against cancer epitopes). As any other viruses, they trigger antiviral response upon systemic administration. Mesenchymal stem cells are immature cells capable of self-renewing and differentiating into many cell types that belong to three germinal layers. Due to their inherent tumor tropism mesenchymal stem cells loaded with oncolytic virus can improve delivery of the therapeutic cargo to cancer sites. Shielding of oncolytic viral construct from antiviral host immune response makes these cells prospective delivery vehicles to even hard-to-reach metastatic neoplastic foci. Use of mesenchymal stem cells has been criticized by some investigators as limiting proliferative abilities of primary cells and increasing the risk of malignant transformation, as well as attenuating therapeutic responses. However, majority of preclinical studies indicate safety and efficacy of mesenchymal stem cells used as carriers of oncolytic viruses. In view of contradictory postulates, the debate continues. The review discusses mesenchymal stem cells as carriers for delivery of genetically engineered oncolytic constructs and focuses on systemic approach to oncoviral treatment of some deadly neoplasms.

Introduction

Despite unquestionable progress in cancer treatment, several malignancies still tend to elude successful cure or medically-induced remission. Continued rise in morbidity in the last twenty years for gliomas, melanoma or pancreatic cancer makes them a major public health concern and a research challenge. Although radically improved outcomes might be unattainable yet, stepwise progress is likely with novel or improved treatments involving immunotherapy, cell-based therapeutics, oncolytic virotherapy and hybrid approaches. Intriguing recoveries from cancer following natural viral infection (e.g. measles) have been known to medicine since early 20th century but this early lead based on use of wild-type adenovirus, poliovirus or Coxsackie virus was marred by virus-associated morbidity and complications and was later abandoned (Kelly et al., 2007). Clinical utility of oncolytic viruses has been steadily regaining ground since the latter part of the 20th century with advances in genetic engineering. Current generation of many oncolytic viral constructs allows targeting and destroying cancer cells while toxicities to surrounding normal tissues are minimized. A concurrent development in cell-based anticancer therapies has led to the concept of oncoviral viruses’ delivery to tumors via cellular carriers. It assumes that certain types of cells pre-loaded ex vivo with some curative cargo can be administered systemically, delivered to and released in target tissues.

1- Introduction

2- Mechanisms regulating MSC differentiation

3- Pericytes as pre-programmed MSC precursors in vivo

4- Discussion and future considerations

References

Abstract

The increasing application of approaches that allow tracing of individual cells over time, together with transcriptomic and epigenomic analyses is changing the way resident stromal stem cells (mesenchymal stem cells) are viewed. Rather than being a defined, homogeneous cell population as described following in vitro expansion, in vivo, these cells are highly programmed according to their resident tissue location. This programming is evidenced by different epigenetic landscapes and gene transcription signatures in cells before any in vitro expansion. This has potentially profound implications for the heterotypic use of these cells in therapeutic tissue engineering applications.

Introduction

The prototypical mesenchymal stem cell (MSC), isolated from bone marrow (BM) was described over 3 decades ago by Friedenstein [1]. This characterisation was later expanded to include a cell type, isolated from connective tissue stroma that can exhibit stem cell properties in vitro [2, 3]. These observations led many researchers to identify cells in multiple organs that had a similar immunophenotype and characteristic s in vitro of MSCs in that they could be differentiated to form osteoblast -like, chondrocyte -like, and adipocyte -like cells. Tissues included, connective tissue of teeth [4, 5] , muscle [6], adipose [7], dermis [8], heart and liver [9]. These cell populations expressed a number of the by now established MSC gene markers and all shared some common characteristics including morphology, adherence to tissue culture plastic, and trilineage differentiation [9, 10].

1- Introduction

2- Materials and methods

3- Results and discussion

4- Conclusion

References

Abstract

In this paper, we report on spatial redistribution of bone marrow mesenchymal stem cells loaded with magnetic nanoparticles under the influence of continuously applied magnetic field. Semiconductor nanoparticles were synthesized by epitaxial growth of a GaN thin layer on magnetic sacrificial core consisting of ZnFe2O4 nanoparticles. Different quantities of nanoparticles were incubated in vitro with mesenchymal stem cells. High density of nanoparticles (50 μg/ml) leads to a decrease in the number of cells during incubation, while the density of nanoparticles as low as 10 μg/ml is enough to drag cells in culture and rearrange them according to the spatial distribution of the magnetic field intensity.

Introduction

Stem cells are defined by their ability to self-renewal and differentiation into more specialized cells, depending on their level of potency [1]. Being easily harvested and cultured, Mesenchymal Stem Cells (MSC) are among the most used stem cells in regenerative medicine. MSC can differentiate into bone, cartilage, fat, tendon, and other different cell lines depending on the given conditions and growth factors [2]. MSC therapeutic potential is enormous and covers a wide medical area, from bone marrow transplantation in blood cancers [3] to the treatment of various diseases like osteoarthritis [4], Crohn`s disease [5], diabetes [6], cardiovascular diseases [7], otorhinolaryngologic pathologies [8], etc. There are several major issues in the therapeutic processes including the non-invasive cellular imaging in high quality transport of therapeutic agent, as well as the remote manipulation in the desired area. The success rate of the therapy based on stem cells depends on the accuracy the cells are delivered to the site of interest. Magnetic resonance imaging (MRI) represents an important tool in cells tracking [9]. The MRI usually includes gadolinium-based contrast agents. Over the last years, however, different types of paramagnetic nanoparticles have been used for tracking cells [10]. The advantage of using nanoparticles for cells tracking relies on the possibility of tuning with the material concentration and chemical composition. Besides tracking, nanoparticles offer the possibility to manipulate with cells and control their spatial position in vivo [11]. The superparamagnetic iron oxide (SPIO), usually stabilized by coating with dextran, gelatine, chitosan or other polymers, is among the most commonly used nanoparticles for cells tracking [12, 13]. Our previous investigations have shown that uncoated gallium nitride nanoparticles (GaN) do not affect the viability and proliferation of endothelial cells [14] and can be used for multifunctional therapeutic purposes which include cells tracking [15]. The use of piezoelectric nanoparticles in combination with magnetic ones could increase the impact of smart materials not only in remote cells imaging but also in the control of the cellular metabolic activity [16-19].

1- Introduction

2- Potential target diseases of genome editing in the cardiovascular field

3- Molecular mechanisms and strategies of genome editing to treat or prevent diseases

4- Current hurdles for therapeutic genome editing

5- Conclusions

References

Abstract

During the past decade, developments in genome editing technology have fundamentally transformed biomedical research. In particular, the CRISPR/Cas9 system has been extensively applied because of its simplicity and ability to alter genomic sequences within living organisms, and an ever increasing number of CRISPR/Cas9-based molecular tools are being developed for a wide variety of applications. While genome editing tools have been used for many aspects of biological research, they also have enormous potential to be used for genome editing therapy to treat a broad range of diseases. For some hematopoietic diseases, clinical trials of therapeutic genome editing with CRISPR/Cas9 are already starting phase I. In the cardiovascular field, genome editing tools have been utilized to understand the mechanisms of diseases such as cardiomyopathy, arrythmia, and lipid metabolism, which now open the door to therapeutic genome editing. Currently, therapeutic genome editing in the cardiovascular field is centered on liver-targeting strategies to reduce cardiovascular risks. Targeting the heart is more challenging. In this review, we discuss the potential applications, recent advances, and current limitations of therapeutic genome editing in the cardiovascular field.

Introduction

The development of genome editing technology was one of the biggest advances in biology in the last decade, and it has revolutionized biomedical research [1-4]. Compared to methods using conventional homologous recombination, which also can modify genomic sequences and are commonly used to generate genetic models, the new genome editing tools have made it much easier and faster to alter genomic DNA sequences within the genome of living organisms. Basically, the genome editing tools harness the endogenous repair process of DNA double-strand breaks (DSBs) generated by programmable nucleases such as zinc finger nucleases (ZFNs) [5], transcription activator-like effector nucleases (TALENs) [6, 7], and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated 9 (Cas9) [2-4] nucleases. In particular, the key initial technological breakthrough was the application of CRISPR/Cas9 system, which was originally discovered as a part of the immune system within bacteria, to eukaryotic genome editing [8]. Because of their simplicity and efficiency, CRISPR/Cas9 genome editing tools have been widely adopted in various scientific fields.

Somatic stem cells expand massively during tissue regeneration, which might require control of cell fitness, allowing elimination of non-competitive, potentially harmful cells. How or if such cells are removed to restore organ function is not fully understood. Here, we show that a substantial fraction of muscle stem cells (MuSCs) undergo necroptosis because of epigenetic rewiring during chronic skeletal muscle regeneration, which is required for efficient regeneration of dystrophic muscles. Inhibition of necroptosis strongly enhances suppression of MuSC expansion in a non-cell-autonomous manner. Prevention of necroptosis in MuSCs of healthy muscles is mediated by the chromatin remodeler CHD4, which directly represses the necroptotic effector Ripk3, while CHD4-dependent Ripk3 repression is dramatically attenuated in dystrophic muscles. Loss of Ripk3 repression by inactivation of Chd4 causes massive necroptosis of MuSCs, abolishing regeneration. Our study demonstrates how programmed cell death in MuSCs is tightly controlled to achieve optimal tissue regeneration.

Introduction

Skeletal muscle regeneration provides a paradigmatic example for the decisive role of tissue-resident stem cells and the necessity of cellular interactions to achieve organ restoration. Muscle stem cells (MuSCs; also known as satellite cells) are indispensable for muscle regeneration but require assistance and instructions from fibroblasts, endothelial cells, fibroadipogenic progenitor cells (FAPs), and immune cells, among others (Charge´ and Rudnicki, 2004; Tidball, 2011; Relaix and Zammit, 2012). Such cells not only provide critical support for MuSCs, enabling their expansion, but might also promote secondary cell death (Saclier et al., 2013; Latroche et al., 2015; Tidball and Villalta, 2010; Joe et al., 2010; Forbes and Rosenthal, 2014). Secondary cell death is not necessarily harmful but might elicit beneficial effects. For example, programmed cell death in FAPs, induced by TNFreleasing inflammatory macrophages, limits fibrosis in acutely damaged skeletal muscles (Lemos et al., 2015). Moreover, MuSCs might engage in a battle of the ‘‘survival of the fittest’’ to ensure that damaged or less fit stem cells are eliminated (Bowling et al., 2019). It has been proposed that tissue stem cells are routinely lost and replaced in a process called neutral cell competition, but many questions related to such a machinery, including the mechanisms by which unfit cells are removed, have yet to be answered (Klein and Simons, 2011). At present, it is not known whether and to what extent MuSCs succumb to programmed cell death in acutely damaged and continuously regenerating dystrophic muscles.

DNA methylation is an epigenetic factor, which plays important roles in embryo and many other diseases development. This factor determines gene expression, and when half of them have CpG islands, DNA methylation and its enzyme effectors have been under the vast studies. Whole genome DNA demethylation is a crucial step of embryogenesis and also cell fate determination in embryos. Therefore, demethylation agents were used as a tool for dedifferentiation and transdifferentiation. Although many of these efforts have been successful, but using this method gave us a vast spectral cell type which is confusing. In this article, we briefly reviewed DNA methylation, and its role in embryogenesis and gene expression. In addition to that, we introduce studies that used this action as a direct method in induction of stem cells and cell fate decision.

Introduction

It has been shown that, epigenetic factors determine transcriptome of cells. These factors determine cell functions and identities [1]. Cell fate determination is among the most significant aspects influenced by these factors [2]. DNA methylation occurring on cytosine in mammals is a major epigenetic factor, which its presence and absence may pose control over 50% of genes, especially developmental-related genes [3]. It has been hypothesized that; DNA demethylation is one of the most significant events in initiation of embryo development after fertilization, which has been named as Zygote Gene Activation (ZGA) [4]. This procedure induces expression of many stemness-related genes. Recently, many studies showed role of DNA demethylation and other epigenetic factors in changing cell fate [2]. It has been proved that, DNA demethylation could change fate of specific somatic cells to another somatic identity in a process named as transdifferentiation [5]. This phenomenon can reprogram somatic cells directly to stem cells [6]. DNA methylation enzyme effectors can establish new fates in differentiation process of stem cells as well [7]. Although it is believed that, disruption of epigenome or reactivation of developmental process in demethylation process could be a potential answer to these phenomena, but related findings have shown that, different roles of DNA demethylation are very confusing to determine. Furthermore, the basic concept and application of this field have been hindered because of its reproducibility and cell fate heterogeneity.

1- Introduction

2- Materials and methods

3- Results

4- Discussion

5- Conclusions

References

Abstract 

Although there have been reports of promising results regarding the transplantation of mesenchymal stem cells (MSCs) for neurodegenerative diseases through the use of neuronal differentiation or control of the microenvironment, traditional surgical transplantation methods like parenchymal or intravenous injection have limitations such as secondary injuries in the brain, infection, and low survival rate of stem cells in the target site. Focused ultrasound (FUS) treatment is an emerging modality for the treatment of brain diseases, including neurodegenerative disorders. The various biological effects of FUS treatment have been investigated; therefore, the goal is now to improve the delivery efficiency and function of MSCs by capitalizing on the advantages of FUS. In this study, we demonstrated that FUS increases MSC transplantation into brain tissue by >2-fold, and that this finding might be related to the activation of intercellular adhesion molecule-1 in endothelial and subendothelial cells and vascular adhesion molecule-1 in endothelial cells.

Introduction

Diseases of the central nervous system (CNS), such as Alzheimer’s disease (AD) and Parkinson’s disease (PD), usually result in degeneration and irreversible damage to the structures and functions of the brain, which is often accompanied by serious cognitive or physical impairments. Many types of novel therapeutic modalities, including targeted medicine (Danon et al., 2019), deep brain stimulation (Lozano et al., 2019), radiosurgery (Jang et al., 2015), and stem cell treatment (McLauchlan and Robertson, 2018), have been evaluated for the treatment of patients with CNS diseases (Chang and Chang, 2017); however, there remains no consensus regarding the choice of effective therapy for neurodegenerative diseases. Stem cell therapy represents a promising treatment modality for CNS diseases, with positive outcomes and the feasibility of the technique being confirmed in recent years (Kamelska-Sadowska et al.,) Early in their development, stem cell applications focused on the replacement of damaged neural structures with neural stem cells (NSCs). One of the goals of NSC therapy is the replacement of dopaminergic neurons in PD, which is characterized by progressive degeneration of dopaminergic neurons in substantia nigra compacta, and many preclinical and clinical trials have been conducted for this purpose (Trounson et al., 2011). Previous studies reported that human NSCs (hNSCs) completely restored and ameliorated the functional defects in 6-hydroxydopamine-induced Parkinsonian mice (Zuo et al., 2017), and that autologous NSCs induced motor recovery and increased dopamine uptake in the transplanted putamen of a patient (Lévesque et al., 2009).