Preventing aging with stem cell rejuvenation: Feasible or infeasible?

Serum-Induced Proliferation of Human Cardiac Stem Cells Is Modulated via TGFβRI/II and SMAD2/3

The ageing phenotype is strongly driven by the exhaustion of adult stem cells (ASCs) and the accumulation of senescent cells. Cardiovascular diseases (CVDs) and heart failure (HF) are strongly linked to the ageing phenotype and are the leading cause of death. As the human heart is considered as an organ with low regenerative capacity, treatments targeting the rejuvenation of human cardiac stem cells (hCSCs) are of great interest. In this study, the beneficial effects of human blood serum on proliferation and senescence of hCSCs have been investigated at the molecular level. We show the induction of a proliferation-related gene expression response by human blood serum at the mRNA level. The concurrent differential expression of the TGFβ target and inhibitor genes indicates the participation of TGFβ signalling in this context. Surprisingly, the application of TGFβ1 as well as the inhibition of TGFβ type I and type II receptor (TGFβRI/II) signalling strongly increased the proliferation of hCSCs. Likewise, both human blood serum and TGFβ1 reduced the senescence in hCSCs. The protective effect of serum on senescence in hCSCs was enhanced by simultaneous TGFβRI/II inhibition. These results strongly indicate a dual role of TGFβ signalling in terms of the serum-mediated effects on hCSCs. Further analysis via RNA sequencing (RNA-Seq) revealed the participation of Ras-inactivating genes wherefore a prevention of hyperproliferation upon serum-treatment in hCSCs via TGFβ signalling and Ras-induced senescence is suggested. These insights may improve treatments of heart failure in the future.

Mitigating Age-Related Ovarian Dysfunction with the Anti-Inflammatory Agent MIT-001

Ovarian aging is a major obstacle in assisted reproductive medicine because it leads to ovarian dysfunction in women of advanced age. Currently, there are no effective treatments to cure age-related ovarian dysfunction. In this study, we investigated the effect of MIT-001 on the function of aged ovaries. Young and old mice were utilized in this study. MIT-001 was intraperitoneally administered, and the number of follicles and oocytes was analyzed. Each group was then retrieved for RNA and protein isolation. Total RNA was subjected to mRNA next-generation sequencing. Protein extracts from ovarian lysates were used to evaluate various cytokine levels in the ovaries. MIT-001 enhanced follicles and the number of oocytes were compared with non-treated old mice. MIT-001 downregulated immune response-related transcripts and cytokines in the ovaries of old mice. MIT-001 modulates the immune complex responsible for generating inflammatory signals and has the potential to restore the function of old ovaries and improve female fertility.

Silibinin Can Promote Bone Regeneration of Selenium Hydrogel by Reducing the Oxidative Stress Pathway in Ovariectomized Rats

Osteoporosis-related bone defects are a major public health concern. Considering poor effects of a singular pharmacological treatment, many have sought combination therapies, including local treatment combined with systemic intervention. Based on recent evidence that selenium and silibinin increase bone formation and bone mineral density, it is hypothesized that systemic administration with silibinin plus local treatment with selenium may have an additive effect on bone regeneration in an OVX rat model with bone defects. To verify this hypothesis, 3-month-old ovariectomized Sprague- Dawley rats (n = 10/gp) were intraperitoneally with a dose of 50 mg/kg silibinin with selenium hydrogel scaffolds implanted into femoral metaphysis bone defect. Moreover, the MC3T3-E1 cells were co-cultured with selenium and silibinin, and observed any change of cell viability, ROS, and osteogenic activity. Experiment results show that the cell mineralization and osteogenic activity of silibinin plus selenium (SSe) group is enormously higher than the control (Con) group and selenium (Se) group, while ROS appears to be immensely reduced. Osteogenic protein expressions such as SIRT1, SOD2, RUNX-2 and OC of SSe group are significantly higher than Con group and Se group. Micro-CT and Histological analysis evaluation display that group SSe, compared with Con group and Se group, presents the strongest effect on bone regeneration, bone mineralization and higher expression of SIRT1 and SOD2. RT-qPCR analysis indicates that SSe group manifests increased SIRT1, SOD1, SOD2 and CAT than the Con group and Se group (p < 0.05). Our current study demonstrates that systemic administration with SIL plus local treatment with Se is a scheme for rapid repair of femoral condylar defects, and these effects may be achieved via reducing the oxidative stress pathway.

OUP accepted manuscript

Stem cell therapies, including stem cell transplantation and rejuvenation of stem cells in situ, are promising avenues for tackling a broad range of diseases. Stem cells can both self-renew and differentiate into other cell types, and play a significant role in the regulation of tissue homeostasis and regeneration after cell degeneration or injury. However, stem cell exhaustion or dysfunction increases with age and impedes the normal function of multiple tissues and systems. Thus, stem cell therapies could provide a solution to aging and age-associated diseases. Here, we discuss recent advances in understanding the mechanisms that regulate stem cell regeneration. We also summarize potential strategies for rejuvenating stem cells that leverage intrinsic and extrinsic factors. These approaches may pave the way toward therapeutic interventions aiming at extending both health and life span.

Neuroprotection Mediated by Human Blood Plasma in Mouse Hippocampal Slice Cultures and in Oxidatively Stressed Human Neurons

Neuroprotection from oxidative stress is critical during neuronal development and maintenance but also plays a major role in the pathogenesis and potential treatment of various neurological disorders and neurodegenerative diseases. Emerging evidence in the murine system suggests neuroprotective effects of blood plasma on the aged or diseased brain. However, little is known about plasma-mediated effects on human neurons. In the present study, we demonstrate the neuroprotective effect mediated by human plasma and the most abundant plasma–protein human serum albumin against oxidative stress in glutamatergic neurons differentiated from human neural crest-derived inferior turbinate stem cells. We observed a strong neuroprotective effect of human plasma and human serum albumin against oxidative stress-induced neuronal death on the single cell level, similar to the one mediated by tumor necrosis factor alpha. Moreover, we detected neuroprotection of plasma and human serum albumin against kainic acid-induced excitatory stress in ex vivo cultured mouse hippocampal tissue slices. The present study provides deeper insights into plasma-mediated neuroprotection ultimately resulting in the development of novel therapies for a variety of neurological and, in particular, neurodegenerative diseases.

Extracellular Microvesicles (MV's) Isolated from 5-Azacytidine-and-Resveratrol-Treated Cells Improve Viability and Ameliorate Endoplasmic Reticulum Stress in Metabolic Syndrome Derived Mesenchymal Stem Cells

Extracellular vesicles (EVs), a spherical membrane fragments including exosomes, are released from several cell types, including mesenchymal stromal cells (MSCs), constitutively or under stimulation. As MVs cargo include DNA, RNA, miRNA, lipids and proteins their have gain special attention in the field of regenerative medicine. Depending on the type of transferred molecules, MVs may exert wide range of biological effects in recipient cells including pro-inflammatory and anti-apoptotic action. In presented paper, we isolated MVs form adipose derived mesenchymal stem cells (ASC) which underwent stimulation with 5-azacytydine and resveratrol (AZA/RES) in order to improve their therapeutic potential. Then, isolated MVs were applied to ASC with impaired cytophysiological properties, isolated from equine metabolic syndrome diagnosed animals. Using RT-PCR, immunofluorescence, ELISA, confocal microscopy and western blot, we have evaluated the effects of MVs on recipient cells. We have found, that MVs derived from AZA/RES treated ASC ameliorates apoptosis, senescence and endoplasmic reticulum (ER) stress in deteriorated cells, restoring their proper functions. The work indicates, that cells treated with AZA/RES through their paracrine action can rejuvenate recipient cells. However, further research needs to be performed in order to fully understand the molecular mechanisms of these bioactive factors action. Graphical Abstract Graphical abstract of presented study.

Stem Cells as a Target for the Delivery of Active Molecules to Skin by Topical Administration

Cutaneous stem cells, gained great attention in the field of regenerative medicine as a potential therapeutic target for the treatment of skin and hair disorders and various types of skin cancers. Cutaneous stem cells play a key role in several processes like the renovation of skin structures in the condition of homeostasis and after injuries, the hair follicle growth and the reconstruction and production of melanocytes. Thus, gaining effective access to skin stem cells for therapeutic interventions that often involve active molecules with non-favorable characteristics for skin absorption is a valuable achievement. The topical route with high patient compliance and several other benefits is gaining increasing importance in basic and applied research. However, the major obstacle for topical drug delivery is the effective barrier provided by skin against penetration of the vast majority of exogenous molecules. The research in this field is focusing more and more on new strategies to circumvent and pass this barrier effectively. In this article the existing approaches are discussed considering physical and chemical methods along with utilization of novel drug delivery systems to enhance penetration of drugs to the skin. In particular, attention has been paid to studies finalized to the delivery of molecules to cutaneous stem cells with the aim of transferring signals, modulating their metabolic program, inducing physiological modifications and stem cell gene therapy.

Rejuvenating Strategies of Tissue-specific Stem Cells for Healthy Aging

Although aging is a physiological process, it has raised interest in the science of aging and rejuvenation because of the increasing burden on the rapidly aging global population. With advanced age, there is a decline in homeostatic maintenance and regenerative responsiveness to the injury of various tissues, thereby contributing to the incidence of age-related diseases. The primary cause of the functional declines that occur along with aging is considered to be the exhaustion of stem cell functions in their corresponding tissues. Age-related changes in the systemic environment, the niche, and stem cells contribute to this loss. Thus, the reversal of stem cell aging at the cellular level might lead to the rejuvenation of the animal at an organismic level and the prevention of aging, which would be critical for developing new therapies for age-related dysfunction and diseases. Here, we will explore the effects of aging on stem cells in different tissues. The focus of this discussion is on pro-youth interventions that target intrinsic stem cell properties, environmental niche component, systemic factors, and senescent cellular clearance, which are promising for developing strategies related to the reversal of aged stem cell function and optimizing tissue repair processes.

Review of the Current Knowledge on the Role of Stem Cell Transplantation in Neurorehabilitation

The management involving stem cell (SC) therapy along with physiotherapy offers tremendous chance for patients after spinal cord injury (SCI), traumatic brain injury (TBI), stroke, etc. However, there are still only a limited number of reports assessing the impact of stem cells (SCs) on the rehabilitation process and/or the results of the simultaneous use of SC and rehabilitation. Additionally, since there is still not enough convincing evidence about the effect of SCT on humans, e.g., in stroke, there have been no studies conducted concerning rehabilitation program formation and expected outcomes. It has been shown that bone marrow-derived mesenchymal stem cell (BMSCs) transplantation in rats combined with hyperbaric oxygen therapy (HBO) can promote the functional recovery of hind limbs after SCI. An anti-inflammatory effect has been shown. One case study showed that, after the simultaneous use of SCT and rehabilitation, an SCI patient progressed from ASIA Grade A to ASIA Grade C. Such promising data in the case of complete tetraplegia could be a breakthrough in the treatment of neurologic disorders in humans. Although SCT appears as a promising method for the treatment of neurological conditions, e.g., complete tetraplegia, much work should be done towards the development of rehabilitation protocols.

Computational Strategies for Niche-Dependent Cell Conversion to Assist Stem Cell Therapy

The field of regenerative medicine has blossomed in recent decades. However, the ultimate goal of tissue regeneration - replacing damaged or aged cells with healthy functioning cells - still faces a number of challenges. In particular, better understanding of the role of the cellular niche in shaping stem cell phenotype and conversion would aid in improving current protocols for stem cell therapies. In this regard, the implementation of novel computational approaches that consider the niche effect on stem cells would be valuable. Here we discuss current problems in stem cell transplantation and rejuvenation, and we propose computational strategies to control niche-dependent cell conversion to overcome them.

Harnessing cellular aging in human stem cell models of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a relentlessly progressive neurodegenerative condition that is invariably fatal, usually within 3 to 5 years of diagnosis. The etiology of ALS remains unresolved and no effective treatments exist. There is therefore a desperate and unmet need for discovery of disease mechanisms to guide novel therapeutic strategies. The single major risk factor for ALS is aging, yet the molecular consequences of cell type‐specific aging remain understudied in this context. Induced pluripotent stem cells (iPSCs) have transformed the standard approach of examining human disease, generating unlimited numbers of disease‐relevant cells from patients, enabling analysis of disease mechanisms and drug screening. However, reprogramming patient cells to iPSCs reverses key hallmarks of cellular age. Therefore, although iPSC models recapitulate some disease hallmarks, a crucial challenge is to address the disparity between the advanced age of onset of neurodegenerative diseases and the fetal‐equivalent maturational state of iPSC‐derivatives. Increasing recognition of cell type‐specific aging paradigms underscores the importance of heterogeneity in ultimately tipping the balance from a state of compensated dysfunction (clinically pre‐symptomatic) to decompensation and progression (irreversible loss of neurological functions). In order to realize the true promise of iPSC technology in ALS, efforts need to prioritize faithfully recapitulating the clinical pathophysiological state, with proportionate emphasis on capturing the molecular sequelae of both cellular age and non‐cell‐autonomous disease mechanisms within this context.

UPRmt regulation and output: a stress response mediated by mitochondrial-nuclear communication

The mitochondrial network is not only required for the production of energy, essential cofactors and amino acids, but also serves as a signaling hub for innate immune and apoptotic pathways. Multiple mechanisms have evolved to identify and combat mitochondrial dysfunction to maintain the health of the organism. One such pathway is the mitochondrial unfolded protein response (UPRmt), which is regulated by the mitochondrial import efficiency of the transcription factor ATFS-1 in C. elegans and potentially orthologous transcription factors in mammals (ATF4, ATF5, CHOP). Upon mitochondrial dysfunction, import of ATFS-1 into mitochondria is reduced, allowing it to be trafficked to the nucleus where it promotes the expression of genes that promote survival and recovery of the mitochondrial network. Here, we discuss recent findings underlying UPRmt signal transduction and how this adaptive transcriptional response may interact with other mitochondrial stress response pathways.