Progress and prospects in stem cell therapy

Mitochondria: A Promising Convergent Target for the Treatment of Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease characterized by the progressive loss of motor neurons, for which current treatment options are limited. Recent studies have shed light on the role of mitochondria in ALS pathogenesis, making them an attractive therapeutic intervention target. This review contains a very comprehensive critical description of the involvement of mitochondria and mitochondria-mediated mechanisms in ALS. The review covers several key areas related to mitochondria in ALS, including impaired mitochondrial function, mitochondrial bioenergetics, reactive oxygen species, metabolic processes and energy metabolism, mitochondrial dynamics, turnover, autophagy and mitophagy, impaired mitochondrial transport, and apoptosis. This review also highlights preclinical and clinical studies that have investigated various mitochondria-targeted therapies for ALS treatment. These include strategies to improve mitochondrial function, such as the use of dichloroacetate, ketogenic and high-fat diets, acetyl-carnitine, and mitochondria-targeted antioxidants. Additionally, antiapoptotic agents, like the mPTP-targeting agents minocycline and rasagiline, are discussed. The paper aims to contribute to the identification of effective mitochondria-targeted therapies for ALS treatment by synthesizing the current understanding of the role of mitochondria in ALS pathogenesis and reviewing potential convergent therapeutic interventions. The complex interplay between mitochondria and the pathogenic mechanisms of ALS holds promise for the development of novel treatment strategies to combat this devastating disease.

Single-Cell RNA Sequencing Reveals Distinct Cardiac-Derived Stromal Cell Subpopulations

Human cardiac-derived c-kit+ stromal cells (CSCs) have demonstrated efficacy in preclinical trials for the treatment of heart failure and myocardial dysfunction. Unfortunately, large variability in patient outcomes and cell populations remains a problem. Previous research has demonstrated that the reparative capacity of CSCs may be linked to the age of the cells: CSCs derived from neonate patients increase cardiac function and reduce fibrosis. However, age-dependent differences between CSC populations have primarily been explored with bulk sequencing methods. In this work, we hypothesized that differences in CSC populations and subsequent cell therapy outcomes may arise from differing cell subtypes within donor CSC samples. We performed single-cell RNA sequencing on four neonatal CSC (nCSC) and five child CSC (cCSC) samples. Subcluster analysis revealed cCSC-enriched clusters upregulated in several fibrosis- and immune response-related genes. Module-based analysis identified upregulation of chemotaxis and ribosomal activity-related genes in nCSCs and upregulation of immune response and fiber synthesis genes in cCSCs. Further, we identified versican and integrin alpha 2 as potential markers for a fibrotic cell subtype. By investigating differences in patient-derived CSC populations at the single-cell level, this research aims to identify and characterize CSC subtypes to better optimize CSC-based therapy and improve patient outcomes.

Pathological Roles of Reactive Oxygen Species in Male Reproduction

Reactive oxygen species (ROS) are free radicals that have at least one unpaired electron and play specific roles in the human body. An imbalance of ROS and antioxidant levels gives rise to a condition called oxidative stress. High levels of ROS in the male reproductive tract can interfere with its normal functioning and can even pose as toxic to the sperm, inhibiting sperm functioning (including motility) and metabolism. Oxidative stress resulting from ROS and lipid peroxidation is one of the major causes of male infertility including infertility in varicocele patients. These may cause DNA and peroxidative damage and apoptosis. Production of ROS in excess also leads to erectile dysfunction (ED). In recent years, studies have also linked oxidative stress with the development, progress, and therapy response of prostate cancer patients. The present study summarizes the pathological roles of ROS in male reproductive problems such as infertility, ED, and prostate cancer and also provide an insight into the probable mechanism through which ROS exert their pathological impact.

In Situ-Forming Collagen/poly-γ-glutamic Acid Hydrogel System with Mesenchymal Stem Cells and Bone Morphogenetic Protein-2 for Bone Tissue Regeneration in a Mouse Calvarial Bone Defect Model

BACKGROUND

Bone marrow-derived mesenchymal stem cells (BMSCs) and bone morphogenetic protein-2 (BMP-2) have been studied for bone repair because they have regenerative potential to differentiate into osteoblasts. The development of injectable and in situ three-dimensional (3D) scaffolds to proliferate and differentiate BMSCs and deliver BMP-2 is a crucial technology in BMSC-based tissue engineering.

METHODS

The proliferation of mouse BMSCs (mBMSCs) in collagen/poly-γ-glutamic acid (Col/γ-PGA) hydrogel was evaluated using LIVE/DEAD and acridine orange and propidium iodide assays. In vitro osteogenic differentiation and the gene expression level of Col/γ-PGA(mBMSC/BMP-2) were assessed by alizarin red S staining and quantitative reverse-transcription polymerase chain reaction. The bone regeneration effect of Col/γ-PGA(mBMSC/BMP-2) was evaluated in a mouse calvarial bone defect model. The cranial bones of the mice were monitored by micro-computed tomography and histological analysis.

RESULTS

The developed Col/γ-PGA hydrogel showed low viscosity below ambient temperature, while it provided a high elastic modulus and viscous modulus at body temperature. After gelation, the Col/γ-PGA hydrogel showed a 3D and interconnected porous structure, which helped the effective proliferation of BMSCs with BMP-2. The Col/γ-PGA (mBMSC/BMP-2) expressed more osteogenic genes and showed effective orthotopic bone formation in a mouse model with a critical-sized bone defect in only 3-4 weeks.

CONCLUSION

The Col/γ-PGA(mBMSC/BMP-2) hydrogel was suggested to be a promising platform by combining collagen as a major component of the extracellular matrix and γ-PGA as a viscosity reducer for easy handling at room temperature in BMSC-based bone tissue engineering scaffolds.

Stem cell therapy as a recent advanced approach in male infertility

Infertility is one of the most common problems in the world that has negative effects on society and infertile people. Among the various causes of infertility, male infertility accounts for almost half of all infertility cases. Despite advances in medicine, current male infertility treatments such as assisted reproductive technology (ART) have not been successful in treating all types of male infertility. Recently, stem cells have been considered as therapeutic targets for many diseases, including infertility, due to their self-renewing and high differentiation. The purpose of this review is to discuss different types of male infertility and the effect of various stem cells against the treatment of male infertility.

When is it Safe to Edit the Human Germline?

In the fall of 2018 Jiankui He shocked the international community with the following announcement: two female babies, "Lulu" and "Nana," whose germlines had been modified by the cutting edge, yet profoundly unsafe CRISPR-Cas9 technology had been born. This event galvanized policy makers and scientists to advocate for more explicit and firm regulation of human germline gene editing (GGE). Recent policy proposals attempt to integrate safety considerations and public input to identify specific types of diseases that may be safe targets for human GGE (Sarkar forthcoming; Guttinger. 2019. "Editing the Reactive Genome: Towards Postgenomic Ethics of Germline Editing." Journal of Applied Philosophy. "Editing the Reactive Genome: Towards Postgenomic Ethics of Germline Editing." Journal of Applied Philosophy. "Editing the Reactive Genome: Towards Postgenomic Ethics of Germline Editing." Journal of Applied Philosophy; Lander et al., 2019). This paper argues these policy proposals are inadequate in different ways. While Sarkar (forthcoming) intends to incorporate input from the disability community for the purpose of deciding the value of human GGE, I argue that his strategy for doing so is inadequate. I'll argue that an iterative, deliberative process is a more appropriate framework for allowing the disability community to inform policy on human GGE. Further policy proposals have been framed in terms of monogenetic or single-gene diseases (Guttinger. 2019. "Editing the Reactive Genome: Towards Postgenomic Ethics of Germline Editing." Journal of Applied Philosophy. "Editing the Reactive Genome: Towards Postgenomic Ethics of Germline Editing." Journal of Applied Philosophy. "Editing the Reactive Genome: Towards Postgenomic Ethics of Germline Editing." Journal of Applied Philosophy; Lander et al., 2019). I argue that this way of conceptualizing disease is not what matters for deciding which disorders are viable candidates for human GGE. Instead, what matters is that (1) the disease in question must have (among its set of causes) genes that have a high degree of causal control with respect to the disease and (2) alternative nucleic acid sequences variants that are likely to produce traits deemed desirable must be identified. Previous policy proposals leave (2) unspecified. What conditions must be met for satisfying condition (2) should not be left to individual scientists to decide for themselves. The present proposal offers some guidance on this issue.

Human Motor Neurons With SOD1-G93A Mutation Generated From CRISPR/Cas9 Gene-Edited iPSCs Develop Pathological Features of Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by gradual degeneration and elimination of motor neurons (MNs) in the motor cortex, brainstem, and spinal cord. Some familial forms of ALS are caused by genetic mutations in superoxide dismutase 1 (SOD1) but the mechanisms driving MN disease are unclear. Identifying the naturally occurring pathology and understanding how this mutant SOD1 can affect MNs in translationally meaningful ways in a valid and reliable human cell model remains to be established. Here, using CRISPR/Cas9 genome editing system and human induced pluripotent stem cells (iPSCs), we generated highly pure, iPSC-derived MNs with a SOD1-G93A missense mutation. With the wild-type cell line serving as an isogenic control and MNs from a patient-derived iPSC line with an SOD1-A4V mutation as a comparator, we identified pathological phenotypes relevant to ALS. The mutant MNs accumulated misfolded and aggregated forms of SOD1 in cell bodies and processes, including axons. They also developed distinctive axonal pathologies. Mutants had axonal swellings with shorter axon length and less numbers of branch points. Moreover, structural and molecular abnormalities in presynaptic and postsynaptic size and density were found in the mutants. Finally, functional studies with microelectrode array demonstrated that the individual mutant MNs exhibited decreased number of spikes and diminished network bursting, but increased burst duration. Taken together, we identified spontaneous disease phenotypes relevant to ALS in mutant SOD1 MNs from genome-edited and patient-derived iPSCs. Our findings demonstrate that SOD1 mutations in human MNs cause cell-autonomous proteinopathy, axonopathy, synaptic pathology, and aberrant neurotransmission.

Transplantation of Adipose Tissue-Derived Stem Cells into Brain Through Cerebrospinal Fluid in Rat Models: Protocol Development and Initial Outcome Data

Background:

Cell therapy is an important strategy for the treatment of incurable diseases including those that occur in the Central Nervous System (CNS). Among different strategies, the method of delivering or transplantation of cells into the brain has shown significant effects on regeneration. In this study, a new protocol has been developed for the transplantation of adipose tissuederived stem cells into the brain through Cerebrospinal Fluid (CSF) in rat models.

Methods:

For this purpose, a wide range of ages (7-30 days old) of male neonates of Wistar rats was used. Moreover, human adipose tissue was obtained from a superficial layer of abdomen through liposuction surgery. The size of the inserted part of needle to access middle cranial fossa and subarachnoid space in animals with an average weight of 10-80 g was determined. In addition, to confirm the entrance of needle into the subarachnoid space, CSF was aspirated slowly and then injection was done within two minutes.

Results:

The findings showed the presence of transplanted human Adipose-Derived Stem Cells (hADSC) in the cerebellum and basal ganglia following three days and also after two months that confirmed the entrance of transplanted cells into the cerebrospinal fluid and migration of them into the brain tissue. All the animals survived after the transplantation process, with the lowest side effects compared to the available conventional methods.

Conclusion:

It can be concluded that the cells could be efficiently transplanted into CSF through subarachnoid space by injection via superior orbital fissure with a minimally invasive technique.

Human induced pluripotent stem cell-derived vascular smooth muscle cells: differentiation and therapeutic potential

Cardiovascular diseases remain the leading cause of death worldwide and current treatment strategies have limited effect of disease progression. It would be desirable to have better models to study developmental and pathological processes and model vascular diseases in laboratory settings. To this end, human induced pluripotent stem cells (hiPSCs) have generated great enthusiasm, and have been a driving force for development of novel strategies in drug discovery and regenerative cell-therapy for the last decade. Hence, investigating the mechanisms underlying the differentiation of hiPSCs into specialized cell types such as cardiomyocytes, endothelial cells, and vascular smooth muscle cells (VSMCs) may lead to a better understanding of developmental cardiovascular processes and potentiate progress of safe autologous regenerative therapies in pathological conditions. In this review, we summarize the latest trends on differentiation protocols of hiPSC-derived VSMCs and their potential application in vascular research and regenerative therapy.

IGFBP-3 plays an important role in senescence as an aging marker

Aging study requires aging markers to measure the degree of aging process. The aging markers such as senescence associated-β-galactosidase (SA-β-gal), lipofuscin, telomere, p53 and p16 have been known in aging study until now. Therefore, we investigated the role of genes and proteins related to aging in young, senescent and H₂O₂-induced old cells to develop a novel aging marker involved in aging mechanism. After cellular aging was compared in young, senescent and H₂O₂-induced old cells using SA-β-galactosidase staining assay, the expression level of genes and proteins in senescent and H₂O₂-induced old cells were compared and analyzed with those of young cells using RT-PCR, western blot and immunofluorescence staining. First of all, the senescent cells and the cells aged by H₂O₂ showed higher level of SA-β-galactosidase staining than young cells. In particular, the expression level of IGFBP-3 was decreased in senescent and H₂O₂-induced old cells compared with young cells. Moreover, the senescent and H2O2-induced old cells showed higher expression levels of p-PI3K, Akt-1, p-mTOR, p-FoxO1 and FoxO1 than young cells. Furthermore, the expression levels of p300, Ac-p53, p53, p-p21 and p16 were significantly increased in senescent and H₂O₂-induced cells compared to young cells. However, the expression level of SIRT-1 was decreased in senescent and H₂O₂-induced old cells compared to young cells. In conclusion, IGFBP-3 up-regulates PI3K/Akt/mTOR signaling pathway and down-regulates autophagy during cell aging. These results suggest that IGFBP-3 could play a key role in aging study as an important aging marker.

Stable Knockdown of Adenosine Kinase by Lentiviral Anti-ADK miR-shRNAs in Wharton's Jelly Stem Cells

Objective

In this study, we describe an efficient approach for stable knockdown of adenosine kinase (ADK) using lentiviral system, in an astrocytoma cell line and in human Wharton’s jelly mesenchymal stem cells (hWJMSCs). These sources of stem cells besides having multilineage differentiation potential and immunomodulatory activities, are easily available in unlimited numbers, do not raise ethical concerns and are attractive for gene manipulation and cell-based gene therapy.

Materials and Methods

In this experimental study, we targeted adenosine kinase mRNA at 3' and performed coding sequences using eight miR-based expressing cassettes of anti-ADK short hairpin RNA (shRNAs). First, these cassettes with scrambled control sequences were cloned into expressing lentiviral pGIPZ vector. Quantitative real time-polymerase chain reaction (qRT-PCR) was used to screen multi-cassettes anti-ADK miR-shRNAs in stably transduced U-251 MG cell line and measuring ADK gene expression at mRNA level. Extracted WJMSCs were characterized using flow cytometry for expressing mesenchymal specific marker (CD44+) and lack of expression of hematopoietic lineage marker (CD45-). Then, the lentiviral vector that expressed the most efficient anti-ADK miR-shRNA, was employed to stably transduce WJMSCs.

Results

Transfection of anti-ADK miR-shRNAs in HEK293T cells using CaPO₄ method showed high efficiency. We successfully transduced U-251 cell line by recombinant lentiviruses and screened eight cassettes of anti-ADK miR- shRNAs in stably transduced U-251 MG cell line by qRT-PCR. RNAi-mediated down-regulation of ADK by lentiviral system indicated up to 95% down-regulation of ADK. Following lentiviral transduction of WJMSCs with anti-ADK miR- shRNA expression cassette, we also implicated, down-regulation of ADK up to 95% by qRT-PCR and confirmed it by western blot analysis at the protein level.

Conclusion

Our findings indicate efficient usage of shRNA cassette for ADK knockdown. Engineered WJMSCs with genome editing methods like CRISPR/cas9 or more safe viral systems such as adeno-associated vectors (AAV) might be an attractive source in cell-based gene therapy and may have therapeutic potential for epilepsy.

Induced pluripotent stem cell: A headway in reprogramming with promising approach in regenerative biology

Since the embryonic stem cells have knocked the doorsteps, they have proved themselves in the field of science, research, and medicines, but the hovered restrictions confine their application in human welfare. Alternate approaches used to reprogram the cells to the pluripotent state were not up to par, but the innovation of induced pluripotent stem cells (iPSCs) paved a new hope for the researchers. Soon after the discovery, iPSCs technology is undergoing renaissance day by day, i.e., from the use of genetic material to recombinant proteins and now only chemicals are employed to convert somatic cells to iPSCs. Thus, this technique is moving straightforward and productive at an astonishing pace. Here, we provide a brief introduction to iPSCs, the mechanism and methods for their generation, their prevailing and prospective applications and the future opportunities that can be expected from them.

Development and Dynamic Regulation of Mitochondrial Network in Human Midbrain Dopaminergic Neurons Differentiated from iPSCs

Mitochondria are critical to neurogenesis, but the mechanisms of mitochondria in neurogenesis have not been well explored. We fully characterized mitochondrial alterations and function in relation to the development of human induced pluripotent stem cell (hiPSC)-derived dopaminergic (DA) neurons. Following directed differentiation of hiPSCs to DA neurons, mitochondria in these neurons exhibit pronounced changes during differentiation, including mature neurophysiology characterization and functional synaptic network formation. Inhibition of mitochondrial respiratory chains via application of complex IV inhibitor KCN (potassium cyanide) or complex I inhibitor rotenone restricted neurogenesis of DA neurons. These results demonstrated the direct importance of mitochondrial development and bioenergetics in DA neuronal differentiation. Our study also provides a neurophysiologic model of mitochondrial involvement in neurogenesis, which will enhance our understanding of the role of mitochondrial dysfunctions in neurodegenerative diseases.

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Mitochondria are essential for the development of hiPSC-derived DA neurons

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Mitochondrial defects suppress maturation and synaptogenesis of DA neurons

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ROS levels positively correlate to DA neuron maturation and synaptic formation

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A model of crosstalk of mitochondrial network to neurogenesis of DA neurons

The Role of Stem Cells in the Treatment of Cerebral Palsy: a Review

Cerebral palsy (CP) is a neuromuscular disease due to injury in the infant's brain. The CP disorder causes many neurologic dysfunctions in the patient. Various treatment methods have been used for the management of CP disorder. However, there has been no absolute cure for this condition. Furthermore, some of the procedures which are currently used for relief of symptoms in CP cause discomfort or side effects in the patient. Recently, stem cell therapy has attracted a huge interest as a new therapeutic method for treatment of CP. Several investigations in animal and human with CP have demonstrated positive potential of stem cell transplantation for the treatment of CP disorder. The ultimate goal of this therapeutic method is to harness the regenerative capacity of the stem cells causing a formation of new tissues to replace the damaged tissue. During the recent years, there have been many investigations on stem cell therapy. However, there are still many unclear issues regarding this method and high effort is needed to create a technology as a perfect treatment. This review will discuss the scientific background of stem cell therapy for cerebral palsy including evidences from current clinical trials.

Magnetic resonance imaging and cell-based neurorestorative therapy after brain injury

Restorative cell-based therapies for experimental brain injury, such as stroke and traumatic brain injury, substantially improve functional outcome. We discuss and review state of the art magnetic resonance imaging methodologies and their applications related to cell-based treatment after brain injury. We focus on the potential of magnetic resonance imaging technique and its associated challenges to obtain useful new information related to cell migration, distribution, and quantitation, as well as vascular and neuronal remodeling in response to cell-based therapy after brain injury. The noninvasive nature of imaging might more readily help with translation of cell-based therapy from the laboratory to the clinic.

Attenuation of teratoma formation by p27 overexpression in induced pluripotent stem cells

BACKGROUND

Pluripotent stem cells, such as embryonic stem cells or induced pluripotent stem cells, have a great potential for regenerative medicine. Induced pluripotent stem cells, in particular, are suitable for replacement of tissue by autologous transplantation. However, tumorigenicity is a major risk in clinical application of both embryonic stem cells and induced pluripotent stem cells. This study explores the possibility of manipulating the cell cycle for inhibition of tumorigenicity.

METHODS

We genetically modified mouse induced pluripotent stem cells (miPSCs) to overexpress p27 tumor suppressor and examined their proliferation rate, gene expression, cardiac differentiation, tumorigenicity, and therapeutic potential in a mouse model of coronary artery ligation.

RESULTS

Overexpression of p27 inhibited cell division of miPSCs, and that inhibition was dependent on the expression level of p27. p27 overexpressing miPSCs had pluripotency characteristics but lost stemness earlier than normal miPSCs during embryoid body and teratoma formation. These cellular characteristics led to none or smaller teratoma when the cells were injected into nude mice. Transplantation of both miPSCs and p27 overexpressing miPSCs into the infarcted mouse heart reduced the infarction size and improved left ventricular function.

CONCLUSIONS

The overexpression of p27 attenuated tumorigenicity by reducing proliferation and earlier loss of stemness of miPSCs. The overexpression of p27 did not affect pluripotency and differentiation characteristics of miPSC. Therefore, regulation of the proliferation rate of miPSCs offers great therapeutic potential for repair of the injured myocardium.

Gene Transfection of Human Turbinate Mesenchymal Stromal Cells Derived from Human Inferior Turbinate Tissues

Human turbinate mesenchymal stromal cells (hTMSCs) are novel stem cells derived from nasal inferior turbinate tissues. They are easy to isolate from the donated tissue after turbinectomy or conchotomy. In this study, we applied hTMSCs to a nonviral gene delivery system using polyethyleneimine (PEI) as a gene carrier; furthermore, the cytotoxicity and transfection efficiency of hTMSCs were evaluated to confirm their potential as resources in gene therapy. DNA-PEI nanoparticles (NPs) were generated by adding the PEI solution to DNA and were characterized by a gel electrophoresis and by measuring particle size and surface charge of NPs. The hTMSCs were treated with DNA-PEI NPs for 4 h, and toxicity of NPs to hTMSCs and gene transfection efficiency were monitored using MTT assay, fluorescence images, and flow cytometry after 24 h and 48 h. At a high negative-to-positive charge ratio, DNA-PEI NPs treatment led to cytotoxicity of hTMSCs, but the transfection efficiency of DNA was increased due to the electrostatic effect between the NPs and the membranes of hTMSCs. Importantly, the results of this research verified that PEI could deliver DNA into hTMSCs with high efficiency, suggesting that hTMSCs could be considered as untapped resources for applications in gene therapy.

Expression profiles of histone lysine demethylases during cardiomyocyte differentiation of mouse embryonic stem cells

AIM

Histone lysine demethylases (KDMs) control the lineage commitments of stem cells. However, the KDMs involved in the determination of the cardiomyogenic lineage are not fully defined. The aim of this study was to investigate the expression profiles of KDMs during the cardiac differentiation of mouse embryonic stem cells (mESCs).

METHODS

An in vitro cardiac differentiation system of mESCs with Brachyury (a mesodermal specific marker) and Flk-1(+)/Cxcr4(+) (dual cell surface biomarkers) selection was used. The expression profiles of KDMs during differentiation were analyzed using Q-PCR. To understand the contributions of KDMs to cardiomyogenesis, the mESCs on differentiation d 3.5 were sorted by FACS into Brachyury(+) cells and Brachyury(-) cells, and mESCs on d 5.5 were sorted into Flk-1(+)/Cxcr4(+) and Flk-1(-)/Cxcr4(-) cells.

RESULTS

mESCs were differentiated into spontaneously beating cardiomyocytes that were visible in embryoid bodies (EBs) on d 7. On d 12-14, all EBs developed spontaneously beating cardiomyocytes. Among the 16 KDMs examined, the expression levels of Phf8, Jarid1a, Jhdm1d, Utx, and Jmjd3 were increased by nearly 2-6-fold on d 14 compared with those on d 0. Brachyury(+) cells showed higher expression levels of Jmjd3, Jmjd2a and Jhdm1d than Brachyury(-) cells. A higher level of Jmjd3 was detected in Flk-1(+)/Cxcr4(+) cells, whereas the level of Jmjd2c was lower in both Brachyury(+) cells and Flk-1(+)/Cxcr4(+) cells.

CONCLUSION

KDMs may play important roles during cardiomyogenesis of mESCs. Our results provide a clue for further exploring the roles of KDMs in the cardiac lineage commitment of mESCs and the potential interference of cardiomyogenesis.

Human leukemia inhibitory factor produced by the ExpressTec method from rice (Oryza sativa L.) is active in human neural stem cells and mouse induced pluripotent stem cells

Stem cell-based therapy has the potential to treat an array of human diseases. However, to study the therapeutic potential and safety of these cells, a scalable cell culture medium is needed that is free of human or bovine-derived serum proteins. Thus, cost-effective recombinant serum proteins and cytokines are needed to produce such mediums. One such cytokine, leukemia inhibitory factor (LIF), has been shown to be a critical paracrine factor that maintains stem cell pluripotency in murine embryonic stem cells and human naïve stem cells while simultaneously inhibiting differentiation. We recently produced recombinant human LIF (rhLIF) in a rice-based protein expression system known as ExpressTec. (12) We described expression of rice-derived rhLIF and demonstrated its biological equivalency to E. coli-derived rhLIF in traditional and embryonic mouse stem cell systems. Here we describe the expression yield of rice-derived rhLIF and the scale up production capacity. We provide further evidence of the efficacy of rice-derived rhLIF in additional stem cell systems including human neural stem cells and mouse induced pluripotent stem (iPS) cells. The expression level, biological activity, and potential for production at commercial scale of rice-derived rhLIF provides a proof-of-principal for ExpressTec-derived proteins to produce regulatory-friendly, high performance, and dependable stem cell media.

Stem cells as new agents for the treatment of infertility: current and future perspectives and challenges

Stem cells are undifferentiated cells that are present in the embryonic, fetal, and adult stages of life and give rise to differentiated cells that make up the building blocks of tissue and organs. Due to their unlimited source and high differentiation potential, stem cells are considered as potentially new therapeutic agents for the treatment of infertility. Stem cells could be stimulated in vitro to develop various numbers of specialized cells including male and female gametes suggesting their potential use in reproductive medicine. During past few years a considerable progress in the derivation of male germ cells from pluripotent stem cells has been made. In addition, stem cell-based strategies for ovarian regeneration and oocyte production have been proposed as future clinical therapies for treating infertility in women. In this review, we summarized current knowledge and present future perspectives and challenges regarding the use of stem cells in reproductive medicine.