Can intermittent fasting help in stem-cell rejuvenation?

Background: Human tissues are sustained by stem cells, the balance between stem cell self-renewal and differentiation, and cell death is the crucial element of haemostasis, which plays a vital role in tissue remodelling. Stem cell therapy is recognized as regenerative medicine. We can stimulate stem cell growth/regeneration through various events. Objectives: In this review, we illustrate whether fasting can stimulate stem cell regeneration. Methodology: A literature survey was undertaken to gather recent research and address the effects of fasting on stem cell renewal, which was the review's purpose. Results: Enterocytes in drosophila were restored after exposure to the dietary restriction. As the result, fasting before etoposide exposure safeguarded mice against harm caused by etoposide when compared with the fed group. A study conducted on the effects of periodic fasting in yeast, mice, and humans shows the increase in lifespan and stress resistance of yeast fasting reduces the risks due to age factors and diseases like diabetes, cardiovascular diseases and promotes a healthy life span of mice and human. Conclusion: Dietary limitations will be used in conjunction with the existing therapeutic approach as adjuvant therapy. It will be a more effective treatment. Fasting has the potential to protect against the negative effects of chemotherapy while also boosting stem cell regeneration, according to preclinical findings. Even though regenerative medicine and stem cell therapy are still in their embryonic stage, greater interventions are needed to show the target pathway of fasting in stem cell renewal. Keywords: Fasting, stem cell regeneration, emerging therapy.

Connective Tissue Growth Factor From Periosteal Tartrate Acid Phosphatase-Positive Monocytes Direct Skeletal Stem Cell Renewal and Fate During Bone Healing

The periosteum is critical for bone healing. Studies have shown that the periosteum contains periosteal stem cells (PSCs) with multidirectional differentiation potential and self-renewal ability. PSCs are activated in early fracture healing and are committed to the chondrocyte lineage, which is the basis of callus formation. However, the mechanism by which PSCs are activated and committed to chondrocytes in bone regeneration remains unclear. Here, we show that tartrate acid phosphatase (TRAP)-positive monocytes secrete CTGF to activate PSCs during bone regeneration. The loss function of TRAP-positive monocytes identifies their specific role during bone healing. Then, the secreted CTGF promotes endochondral ossification and activates PSCs in mouse bone fracture models. The secreted CTGF enhances PSC renewal by upregulating the expression of multiple pluripotent genes. CTGF upregulates c-Jun expression through αVβ5 integrin. Then, c-Jun transcription activates the transcription of the pluripotent genes Sox2, Oct4, and Nanog. Simultaneously, CTGF also activates the transcription and phosphorylation of Smad3 through αVβ5 integrin, which is the central gene in chondrogenesis. Our study indicates that TRAP-positive monocyte-derived CTGF promotes bone healing by activating PSCs and directing lineage commitment and that targeting PSCs may be an effective strategy for preventing bone non-union.

Crosstalk of the Wnt/β-Catenin Signaling Pathway in the Induction of Apoptosis on Cancer Cells

The Wnt/β-catenin signaling pathway plays a major role in cell survival and proliferation, as well as in angiogenesis, migration, invasion, metastasis, and stem cell renewal in various cancer types. However, the modulation (either up- or downregulation) of this pathway can inhibit cell proliferation and apoptosis both through β-catenin-dependent and independent mechanisms, and by crosstalk with other signaling pathways in a wide range of malignant tumors. Existing studies have reported conflicting results, indicating that the Wnt signaling can have both oncogenic and tumor-suppressing roles, depending on the cellular context. This review summarizes the available information on the role of the Wnt/β-catenin pathway and its crosstalk with other signaling pathways in apoptosis induction in cancer cells and presents a modified dual-signal model for the function of β-catenin. Understanding the proapoptotic mechanisms induced by the Wnt/β-catenin pathway could open new therapeutic opportunities.

Kv1.1 channels regulate early postnatal neurogenesis in mouse hippocampus via the TrkB signaling pathway

In the postnatal brain, neurogenesis occurs only within a few regions, such as the hippocampal sub-granular zone (SGZ). Postnatal neurogenesis is tightly regulated by factors that balance stem cell renewal with differentiation, and it gives rise to neurons that participate in learning and memory formation (Anacker and Hen, 2017; Bond et al., 2015; Toda et al., 2019). The Kv1.1 channel, a voltage-gated potassium channel, was previously shown to suppress postnatal neurogenesis in the SGZ in a cell-autonomous manner. In this study, we clarified the physiological and molecular mechanisms underlying Kv1.1-dependent postnatal neurogenesis. First, we discovered that the membrane potential of neural progenitor cells is highly dynamic during development. We further established a multinomial logistic regression model for cell type classification based on the biophysical characteristics and corresponding cell markers. We found that loss of Kv1.1 channel activity causes significant depolarization of type 2b neural progenitor cells. This depolarization is associated with increased tropomyosin receptor kinase B (TrkB) signaling and proliferation of neural progenitor cells; suppressing TrkB signaling reduces the extent of postnatal neurogenesis. Thus, our study defines the role of the Kv1.1 potassium channel in regulating the proliferation of postnatal neural progenitor cells in the mouse hippocampus.

Transcriptomic mapping on Notch signaling in A luminal phenotype breast cancer.

e12539 Background: The Notch signaling pathway plays an important role in cell-differentiation, survival, proliferation, stem-cell renewal, and in determining cell fate during development and morphogenesis. The dysregulation of the Notch pathways contributes to carcinogenesis, cancer stem cell renewal, angiogenesis, and chemo-resistance. Elevated levels of Notch receptors and ligands have been associated with cancer-progression and poor survival. A less explored function of Notch pathways in cancer is their role in leukocyte homing and activation. Understanding their role and relationship with immune infiltrates is an area of interest in cancer research. Methods: The expression of four different Notch genes (Notch1, Notch2, Notch3 and Notch4) was explored in relation with A luminal breast cancer patient outcome using transcriptomic data (Affymetrix dataset, exploratory cohort) and the METABRIC study (validation cohort). The TIMER online tool was used to explore the association of the identified notch and immune infiltration, and the TCGA and METABRIC studies to analyze the correlation between notch1 - 4 expression and genomic signatures of immune activation. Results: We identified 2 individual genes called Notch1 and Notch2, which predict favorable prognosis in luminal A breast cancer. Their expression positively correlated with the presence of immune infiltrates within the tumor (dendritic cells, CD4+ T cells, neutrophils, CD8+ T cells and B cells), with markers of T cell activation and antigen presentation, and with gene signatures of immune surveillance (cytotoxic T lymphocyte activation and IFN gamma signature). By contrast Notch3 and Notch4 which predicted for detrimental outcome were not associated with any of these parameters. Conclusions: Our analysis identifies a Notch signature composed of 2 genes with potential to recognize immune infiltrated and activated A luminal phenotype breast cancers with favorable prognosis.

Interplay between RNA Viruses and Promyelocytic Leukemia Nuclear Bodies

Promyelocytic leukemia nuclear bodies (PML NBs) are nuclear membrane-less sub structures that play a critical role in diverse cellular pathways including cell proliferation, DNA damage, apoptosis, transcriptional regulation, stem cell renewal, alternative lengthening of telomeres, chromatin organization, epigenetic regulation, protein turnover, autophagy, intrinsic and innate antiviral immunity. While intrinsic and innate immune functions of PML NBs or PML NB core proteins are well defined in the context of nuclear replicating DNA viruses, several studies also confirm their substantial roles in the context of RNA viruses. In the present review, antiviral activities of PML NBs or its core proteins on diverse RNA viruses that replicate in cytoplasm or the nucleus were discussed. In addition, viral counter mechanisms that reorganize PML NBs, and specifically how viruses usurp PML NB functions in order to create a cellular environment favorable for replication and pathogenesis, are also discussed.

Hypoxia in Cell Reprogramming and the Epigenetic Regulations

Cellular reprogramming is a fundamental topic in the research of stem cells and molecular biology. It is widely investigated and its understanding is crucial for learning about different aspects of development such as cell proliferation, determination of cell fate and stem cell renewal. Other factors involved during development include hypoxia and epigenetics, which play major roles in the development of tissues and organs. This review will discuss the involvement of hypoxia and epigenetics in the regulation of cellular reprogramming and how interplay between each factor can contribute to different cellular functions as well as tissue regeneration.