Targeting the stem cell niche micro-environment as therapeutic strategies in aging

Cell-based regenerative and rejuvenation strategies for treating neurodegenerative diseases

Neurodegenerative diseases including Alzheimer's and Parkinson's disease are age-related disorders which severely impact quality of life and impose significant societal burdens. Cellular senescence is a critical factor in these disorders, contributing to their onset and progression by promoting permanent cell cycle arrest and reducing cellular function, affecting various types of cells in brain. Recent advancements in regenerative medicine have highlighted "R3" strategies-rejuvenation, regeneration, and replacement-as promising therapeutic approaches for neurodegeneration. This review aims to critically analyze the role of cellular senescence in neurodegenerative diseases and organizes therapeutic approaches within the R3 regenerative medicine paradigm. Specifically, we examine stem cell therapy, direct lineage reprogramming, and partial reprogramming in the context of R3, emphasizing how these interventions mitigate cellular senescence and counteracting aging-related neurodegeneration. Ultimately, this review seeks to provide insights into the complex interplay between cellular senescence and neurodegeneration while highlighting the promise of cell-based regenerative strategies to address these debilitating conditions.

Bone metastases of prostate cancer: Molecular mechanisms, targeted diagnosis and targeted therapy (Review)

Prostate cancer (PCa) is second only to lung cancer in terms of death among men worldwide. Advanced PCa frequently results in bone metastases, which occur in ~90% of patients and frequently result in severe skeleton‑related events. Currently, the treatment for this disease is limited to alleviating its clinical symptoms and cannot provide a complete cure. Therefore, the development of novel treatment strategies is particularly important. In recent years, numerous novel strategies for the diagnosis and treatment of PCa have emerged, resulting in good clinical efficacy. For example, strategies targeting prostate specific membrane antigen, poly ADP‑ribose polymerase and programmed cell death protein 1 have been applied to PCa‑induced bone metastasis, and have shown initial efficacy and great potential. Therefore, understanding the molecular mechanisms underlying the formation of bone metastases in patients with PCa is of importance for the effective management of this disease. The purpose of the present review is to comprehensively outline the roles of protein‑coding genes and non‑coding RNAs in the development of bone metastases of PCa to elucidate their significance in the management of PCa. The aim is to offer clinicians and researchers a comprehensive understanding of this topic.

Innovative approaches to boost mesenchymal stem cells efficacy in myocardial infarction therapy

Stem cell-based therapy has emerged as a promising approach for heart repair, potentially regenerating damaged heart tissue and improving outcomes for patients with heart disease. However, the efficacy of stem cell-based therapies remains limited by several challenges, including poor cell survival, low retention rates, poor integration, and limited functional outcomes. This article reviews current enhancement strategies to optimize mesenchymal stem cell therapy for cardiac repair. Key approaches include optimizing cell delivery methods, enhancing cell engraftment, promoting cell functions through genetic and molecular modifications, enhancing the paracrine effects of stem cells, and leveraging biomaterials and tissue engineering techniques. By focusing on these enhancement techniques, the paper highlights innovative approaches that can potentially transform stem cell therapy into a more viable and effective treatment option for cardiac repair. The ongoing research and technological advancements continue to push the boundaries, hoping to make stem cell therapy a mainstream treatment for heart disease.

Skeletal muscle stem cells modulate niche function in Duchenne muscular dystrophy mouse through YY1-CCL5 axis

Adult skeletal muscle stem cells (MuSCs) are indispensable for muscle regeneration and tightly regulated by macrophages (MPs) and fibro-adipogenic progenitors (FAPs) in their niche. Deregulated MuSC/MP/FAP interactions and the ensuing inflammation and fibrosis are hallmarks of dystrophic muscle. Here we demonstrate intrinsic deletion of transcription factor Yin Yang 1 (YY1) in MuSCs exacerbates dystrophic pathologies by altering composition and heterogeneity of MPs and FAPs. Further analysis reveals YY1 loss induces expression of immune genes in MuSCs, including C-C motif chemokine ligand 5 (Ccl5). Augmented CCL5 secretion promotes MP recruitment via CCL5/C-C chemokine receptor 5 (CCR5) crosstalk, which subsequently hinders FAP clearance through elevated Transforming growth factor-β1 (TGFβ1). Maraviroc-mediated pharmacological blockade of the CCL5/CCR5 axis effectively mitigates muscle dystrophy and improves muscle performance. Lastly, we demonstrate YY1 represses Ccl5 transcription by binding to its enhancer thus facilitating promoter-enhancer looping. Altogether, our study demonstrates the critical role of MuSCs in actively shaping their niche and provides novel insight into the therapeutic intervention of muscle dystrophy.

Stem cell therapy for the treatment of psychiatric disorders: a real hope for the next decades

In this review, it is evaluated the progress in the application of stem cell therapy to ameliorate the symptoms of bipolar disorder, major depression, schizophrenia, and autism. These disorders are highly prevalent in clinical medicine and are responsible for high levels of psychosocial disability among patients. All of them share common biomedical features, such as complex and variable genetic substrates, significant susceptibility to environmental changes, and insufficient knowledge of their pathogenesis. In addition, the responsiveness of patients to pharmacological treatment is heterogeneous, and in some cases, no treatment is available. Therefore, the development of stem cell-based regenerative medicine and its possible combination with emerging therapeutic approaches that promote neural plasticity are expected to advance neuropsychiatry in the next few decades.

L-carnitine cause to increase cell proliferation of C-Kit+ hematopoietic progenitor cells via decreasing the PI3K and FOXO-1 protein expression

BACKGROUND

Stem cell-based therapy has emerged as an attractive approach for regenerative medicine. Poor survival and maintenance of the cells used in regenerative medicine are considered as serious barriers to enhance the efficacy of the cell therapy. Using some antioxidants has been reported to prevent the aging of stem cells, and finding effective factors to reduce the senescence of these cells has impressive potential in cell therapy. The PI3K pathway adversely regulates the transcription factors known as FOXO, which are thought to have an inhibitory influence on cell proliferation. By downregulating FOXO and other targets, PI3K signaling controls the growth of cells. For this reason, the aim of the present study is to investigate the effect of L-carnitine (LC) as antioxidant on the cell proliferation and the protein expression of PI3K and FOXO.

METHODS

For understanding the in vitro effect of LC on the PI3K and FOXO-1 expression of C-kit+ hematopoietic progenitor cells, the bone marrow mononuclear cells were isolated, and C-kit+ cells was enriched by the magnetic-activated cell sorting (MACS). Next, the identification of enriched C-kit+ cells were done by flowcytometry and immunocytochemistry. Then, C-kit+ cells were treated with 0.2 mM LC, the cells were collected at the end of the treatment period (48 h), and the proteins were extracted. In the following, the protein expression of PI3K and FOXO-1 was measured by western blotting. In addition, flowcytometry was done to assess the Ki-67 expression as a key marker for cell proliferation investigation.

RESULTS

0.2 mM LC cause to significantly decrease in the protein expression of PI3K and FOXO-1 (*P<0.05 and **P<0.01, respectively). Also, the expression of Ki-67 was significantly increased in the presence of 0.2 mM LC (***P<0.001).

CONCLUSION

Briefly, LC can be considered an effective factor in increasing the proliferation of C-kit+ cells via some signaling pathways.

The Role of Inflammatory Cascade and Reactive Astrogliosis in Glial Scar Formation Post-spinal Cord Injury

Reactive astrogliosis and inflammation are pathologic hallmarks of spinal cord injury. After injury, dysfunction of glial cells (astrocytes) results in glial scar formation, which limits neuronal regeneration. The blood-spinal cord barrier maintains the structural and functional integrity of the spinal cord and does not allow blood vessel components to leak into the spinal cord microenvironment. After the injury, disruption in the spinal cord barrier causes an imbalance of the immunological microenvironment. This triggers the process of neuroinflammation, facilitated by the actions of microglia, neutrophils, glial cells, and cytokines production. Recent work has revealed two phenotypes of astrocytes, A1 and A2, where A2 has a protective type, and A1 releases neurotoxins, further promoting glial scar formation. Here, we first describe the current understanding of the spinal cord microenvironment, both pre-, and post-injury, and the role of different glial cells in the context of spinal cord injury, which forms the essential update on the cellular and molecular events following injury. We aim to explore in-depth signaling pathways and molecular mediators that trigger astrocyte activation and glial scar formation. This review will discuss the activated signaling pathways in astrocytes and other glial cells and their collaborative role in the development of gliosis through inflammatory responses.

Gut aging: A wane from the normal to repercussion and gerotherapeutic strategies

Globally, age-related diseases represent a significant public health concern among the elderly population. In aging, healthy organs and tissues undergo structural and functional changes that put the aged adults at risk of diseases. Some of the age-related diseases include cancer, atherosclerosis, brain disorders, muscle atrophy (sarcopenia), gastrointestinal (GIT) disorders, etc. In organs, a decline in stem cell function is the starting point of many conditions and is extremely important in GIT disorder development. Many studies have established that aging affects stem cells and their surrounding supportive niche components. Although there is a significant advancement in treating intestinal aging, the rising elderly population coupled with a higher occurrence of chronic gut ailments necessitates more effective therapeutic approaches to preserve gut health. Notable therapeutic strategies such as Western medicine, traditional Chinese medicine, and other health-promotion interventions have been reported in several studies to hold promise in mitigating age-related gut disorders. This review highlights findings across various facets of gut aging with a focus on aging-associated changes of intestinal stem cells and their niche components, thus a deviation from the normal to repercussion, as well as essential therapeutic strategies to mitigate intestinal aging.

Roles of Microenvironment on Mesenchymal Stem Cells Therapy for Osteoarthritis

Osteoarthritis (OA) induced microenvironmental alterations are a common and unavoidable phenomenon that greatly exacerbate the pathologic process of OA. Imbalances in the synthesis and degradation of cartilage extracellular matrix (ECM) have been reported to be associated with an adverse microenvironment. Stem cell therapy is a promising treatment for OA, and mesenchymal stem cells (MSCs) are the main cell sources for this therapy. With multispectral differentiation and immunomodulation, MSCs can effectively regulate the microenvironment of articular cartilage, ameliorate inflammation, promote regeneration of damaged cartilage, and ultimately alleviate OA symptoms. However, the efficacy of MSCs in the treatment of OA is greatly influenced by articular cavity microenvironments. This article reviews the five microenvironments of OA articular cavity, including inflammatory microenvironment, senescence microenvironment, hypoxic microenvironment, high glucose microenvironment and high lipid environment, focus on the positive and negative effects of OA microenvironments on the fate of MSCs. In this regard, we emphasize the mechanisms of the current use of MSCs in OA treatment, as well as its limitations and challenges.

Bone marrow derived mesenchymal stem cells restored GLUT1 expression in the submandibular salivary glands of ovariectomized rats

OBJECTIVE

Loss of ovarian function in menopause is commonly associated with salivary gland dysfunction. The aim is to study the possible therapeutic effect of bone marrow mesenchymal stem cells (BM-MSCs) on the altered structure of the submandibular salivary glands (SMGs) of ovariectomized rats.

DESIGN

Twenty-four female, adult, Wistar rats were used and distributed into three groups (8 rats/group). The control group included sham-operated rats. The ovariectomized group consisted of rats with removed ovaries. The third group consisted of ovariectomized rats received injections, via tail, of MSCs extracted from bone marrow of 3-weeks-old rat hind limb (BM-MSC group). Four weeks after BM-MSC transplantation, the bone mineral density (BMD) of the femur was detected. The SMG was dissected and processed for histological, immunohistochemical, and histomorphometric analyses.

RESULTS

The ovariectomized rats depicted low BMD in the femur. The SMG acini revealed atrophy. The ductal and acinar cells depicted vacuolization and abnormal nuclear histology. GLUT1 immunostaining was decreased in SMG ducts. The BM-MSC group resumed the normal SMG histology and GLUT1 immunolabelling.

CONCLUSIONS

BM-MSC therapy restored the normal SMG structure and GLUT1 immunostaining in the treated ovariectomized rats, suggesting improved glucose transporting function.

Stem cell transplantation in cerebrovascular accidents: A global bibliometric analysis (2000-2023)

BACKGROUND

Cerebrovascular accident (CVA) is a major global contributor to death and disability. As part of its medical management, researchers have recognized the importance of promising neuroprotective strategies, where stem cell transplantation (SCT) is thought to confer advantages via trophic and neuroprotective effects.

AIM

To evaluate the current state of research on SCT in patients with CVA, assess key trends and highlight literature gaps.

METHODS

PubMed was screened for SCT in CVA-related articles in October 2023, for each country during the period between 2000 and 2023. Using the World Bank data, total population and gross domestic product were collected for comparison. VOSviewer_1.6.19 was used to create the VOS figure using the results of the same query. Graphs and tables were obtained using Microsoft Office Excel.

RESULTS

A total of 6923 studies were identified on SCT in CVA, making 0.03% of all published studies worldwide. Approximately, 68% were conducted in high-income countries, with a significant focus on mesenchymal stem cells. The journal "Stroke" featured the largest share of these articles, with mesenchymal SCT having the highest rate of inclusion, followed by hematopoietic SCT. Over time, there has been a noticeable shift from in vitro studies, which assess stem cell proliferation and neurogenesis, to in vivo studies aimed at evaluating efficacy and safety. Additionally, the number of reviews increased along this approach.

CONCLUSION

This bibliometric analysis provides a comprehensive guide for physicians and researchers in the field through an objective overview of research activity, and highlights both current trends and gaps. Having a potential therapeutic role in CVA, more research is needed in the future to focus on different aspects of SCT, aiming to reach a better treatment strategy and improve life quality in patients.

Stem cells, Notch-1 signaling, and oxidative stress: a hellish trio in cancer development and progression within the airways. Is there a role for natural compounds?

Notch-1 signaling plays a crucial role in stem cell maintenance and in repair mechanisms in various mucosal surfaces, including airway mucosa. Persistent injury can induce an aberrant activation of Notch-1 signaling in stem cells leading to an increased risk of cancer initiation and progression. Chronic inflammatory respiratory disorders, including chronic obstructive pulmonary disease (COPD) is associated with both overactivation of Notch-1 signaling and increased lung cancer risk. Increased oxidative stress, also due to cigarette smoke, can further contribute to promote cancer initiation and progression by amplifying inflammatory responses, by activating the Notch-1 signaling, and by blocking regulatory mechanisms that inhibit the growth capacity of stem cells. This review offers a comprehensive overview of the effects of aberrant Notch-1 signaling activation in stem cells and of increased oxidative stress in lung cancer. The putative role of natural compounds with antioxidant properties is also described.

The role of the hematopoietic stem/progenitor cells-derived extracellular vesicles in hematopoiesis

Hematopoietic stem cells (HSCs) are tightly regulated by specific microenvironments called niches to produce an appropriate number of mature blood cell types. Self-renewal and differentiation are two hallmarks of hematopoietic stem and progenitor cells, and their balance is critical for proper functioning of blood and immune cells throughout life. In addition to cell-intrinsic regulation, extrinsic cues within the bone marrow niche and systemic factors also affect the fate of HSCs. Despite this, many paracrine and endocrine factors that influence the function of hematopoietic cells remain unknown. In hematological malignancies, malignant cells remodel their niche into a permissive environment to enhance the survival of leukemic cells. These events are accompanied by loss of normal hematopoiesis. It is well known that extracellular vehicles (EVs) mediate intracellular interactions under physiological and pathological conditions. In other words, EVs transfer biological information to surrounding cells and contribute not only to physiological functions but also to the pathogenesis of some diseases, such as cancers. Therefore, a better understanding of cell-to-cell interactions may lead to identification of potential therapeutic targets. Recent reports have suggested that EVs are evolutionarily conserved constitutive mediators that regulate hematopoiesis. Here, we focus on the emerging roles of EVs in normal and pathological conditions, particularly in hematological malignancies. Owing to the high abundance of EVs in biological fluids, their potential use as biomarkers and therapeutic tools is discussed.

Emerging Landscape of Mesenchymal Stem Cell Senescence Mechanisms and Implications on Therapeutic Strategies

Mesenchymal stem cells (MSCs) hold significant promise for regenerative medicine and tissue engineering due to their unique multipotent differentiation ability and immunomodulatory properties. MSC therapy is widely discussed and utilized in clinical treatment. However, during both in vitro expansion and in vivo transplantation, MSCs are prone to senescence, an irreversible growth arrest characterized by morphological, gene expression, and functional changes in genomic regulation. The microenvironment surrounding MSCs plays a crucial role in modulating their senescence phenotype, influenced by factors such as hypoxia, inflammation, and aging status. Numerous strategies targeting MSC senescence have been developed, including senolytics and senomorphic agents, antioxidant and exosome therapies, mitochondrial transfer, and niche modulation. Novel approaches addressing replicative senescence have also emerged. This paper comprehensively reviews the current molecular manifestations of MSC senescence, addresses the environmental impact on senescence, and highlights potential therapeutic strategies to mitigate senescence in MSC-based therapies. These insights aim to enhance the efficacy and understanding of MSC therapies.

Natural small molecules synergize mesenchymal stem cells for injury repair in vital organs: a comprehensive review

Mesenchymal stem cells (MSCs) therapy is a highly researched treatment that has the potential to promote immunomodulation and anti-inflammatory, anti-apoptotic, and antimicrobial activities. It is thought that it can enhance internal organ function, reverse tissue remodeling, and achieve significant organ repair and regeneration. However, the limited infusion, survival, and engraftment of transplanted MSCs diminish the effectiveness of MSCs-based therapy. Consequently, various preconditioning methods have emerged as strategies for enhancing the therapeutic effects of MSCs and achieving better clinical outcomes. In particular, the use of natural small molecule compounds (NSMs) as a pretreatment strategy is discussed in this narrative review, with a focus on their roles in regulating MSCs for injury repair in vital internal organs. Additionally, the discussion focuses on the future directions and challenges of transforming mesenchymal stem cell research into clinical applications.

Fructose vs. glucose: modulating stem cell growth and function through sugar supplementation

In multicellular organisms, stem cells are impacted by microenvironmental resources such as nutrient availability and oxygen tension for their survival, growth, and differentiation. However, the accessibility of these resources in the pericellular environment greatly varies from organ to organ. This divergence in resource availability leads to variations in the potency and differentiation potential of stem cells. This study aimed to explore the distinct effects of glucose and fructose, as well as different oxygen tensions, on the growth dynamics, cytokine production, and differentiation of stem cells. We showed that replacing glucose with fructose subjected stem cells to stress, resulting in increased Hif1α expression and stability, which in turn led to a reduction in cell proliferation, and alterations in cytokine production. However, fructose failed to induce differentiation of human mesenchymal stem cells (hMSCs) as well as mouse fibroblasts into mature adipocytes compared to glucose, despite the upregulation of key markers of adipogenesis, including C/EBPβ, and PPARγ. Conversely, we showed that fructose induced undifferentiated mouse fibroblasts to release cytokines associated with senescence, including IL1α1, IL6, IL8, MCP1, and TNF1α, suggesting that these cells were undergoing lipolysis. Taken together, our results suggest that altering the culture conditions through changes in hexose levels and oxygen tension places considerable stress on stem cells. Additional research is required to further characterize the mechanisms governing stem cell response to their microenvironments.

How aging influences the gut-bone marrow axis and alters hematopoietic stem cell regulation

The gut microbiome has come to prominence across research disciplines, due to its influence on major biological systems within humans. Recently, a relationship between the gut microbiome and hematopoietic system has been identified and coined the gut-bone marrow axis. It is well established that the hematopoietic system and gut microbiome separately alter with age; however, the relationship between these changes and how these systems influence each other demands investigation. Since the hematopoietic system produces immune cells that help govern commensal bacteria, it is important to identify how the microbiome interacts with hematopoietic stem cells (HSCs). The gut microbiota has been shown to influence the development and outcomes of hematologic disorders, suggesting dysbiosis may influence the maintenance of HSCs with age. Short chain fatty acids (SCFAs), lactate, iron availability, tryptophan metabolites, bacterial extracellular vesicles, microbe associated molecular patterns (MAMPs), and toll-like receptor (TLR) signalling have been proposed as key mediators of communication across the gut-bone marrow axis and will be reviewed in this article within the context of aging.

Effects of the MCF-7 Exhausted Medium on hADSC Behaviour

Stem cells possess the ability to differentiate into different lineages and the ability to self-renew, thus representing an excellent tool for regenerative medicine. They can be isolated from different tissues, including the adipose tissue. Adipose tissue and human adipose-derived stem cells (hADSCs) are privileged candidates for regenerative medicine procedures or other plastic reconstructive surgeries. The cellular environment is able to influence the fate of stem cells residing in the tissue. In a previous study, we exposed hADSCs to an exhausted medium of a breast cancer cell line (MCF-7) recovered at different days (4, 7, and 10 days). In the same paper, we inferred that the medium was able to influence the behaviour of stem cells. Considering these results, in the present study, we evaluated the expression of the major genes related to adipogenic and osteogenic differentiation. To confirm the gene expression data, oil red and alizarin red colorimetric assays were performed. Lastly, we evaluated the expression of miRNAs influencing the differentiation process and the proliferation rate, maintaining a proliferative state. The data obtained confirmed that cells exposed to the medium maintained a stem and proliferative state that could lead to a risky proliferative phenotype.

Mesenchymal stem cell-derived exosomes for management of prostate cancer: An updated view

Prostate cancer represents the second most prevalent form of cancer found in males, and stands as the fifth primary contributor to cancer-induced mortality on a global scale. Research has shown that transplanted mesenchymal stem cells (MSCs) can migrate by homing to tumor sites in the body. In prostate cancer, researchers have explored the fact that MSC-based therapies (including genetically modified delivery vehicles or vectors) and MSC-derived exosomes are emerging as attractive options to improve the efficacy and safety of traditional cancer therapies. In addition, researchers have reported new insights into the application of extracellular vesicle (EV)-MSC therapy as a novel treatment option that could provide a more effective and targeted approach to prostate cancer treatment. Moreover, the new generation of exosomes, which contain biologically functional molecules as signal transducers between cells, can simultaneously deliver different therapeutic agents and induce an anti-tumor phenotype in immune cells and their recruitment to the tumor site. The results of the current research on the use of MSCs in the treatment of prostate cancer may be helpful to researchers and clinicians working in this field. Nevertheless, it is crucial to emphasize that although dual-role MSCs show promise as a therapeutic modality for managing prostate cancer, further investigation is imperative to comprehensively grasp their safety and effectiveness. Ongoing clinical trials are being conducted to assess the viability of MSCs in the management of prostate cancer. The results of these trials will help determine the viability of this approach. Based on the current literature, engineered MSCs-EV offer great potential for application in targeted tumor therapy.

Alternative pre-mRNA splicing in stem cell function and therapeutic potential: A critical review of current evidence

Alternative splicing is a crucial regulator in stem cell biology, intricately influencing the functions of various biological macromolecules, particularly pre-mRNAs and the resultant protein isoforms. This regulatory mechanism is vital in determining stem cell pluripotency, differentiation, and proliferation. Alternative splicing's role in allowing single genes to produce multiple protein isoforms facilitates the proteomic diversity that is essential for stem cells' functional complexity. This review delves into the critical impact of alternative splicing on cellular functions, focusing on its interaction with key macromolecules and how this affects cellular behavior. We critically examine how alternative splicing modulates the function and stability of pre-mRNAs, leading to diverse protein expressions that govern stem cell characteristics, including pluripotency, self-renewal, survival, proliferation, differentiation, aging, migration, somatic reprogramming, and genomic stability. Furthermore, the review discusses the therapeutic potential of targeting alternative splicing-related pathways in disease treatment, particularly focusing on the modulation of RNA and protein interactions. We address the challenges and future prospects in this field, underscoring the need for further exploration to unravel the complex interplay between alternative splicing, RNA, proteins, and stem cell behaviors, which is crucial for advancing our understanding and therapeutic approaches in regenerative medicine and disease treatment.