Evidence has accumulated that postnatal tissues contain developmentally early stem cells that remain in a dormant state as well as stem cells that are more proliferative, supplying tissue-specific progenitor cells and thus playing a more active role in the turnover of adult tissues. The most primitive, dormant, postnatal tissue-derived stem cells, called very small embryonic like stem cells (VSELs), are regulated by epigenetic changes in the expression of certain parentally imprinted genes, a molecular phenomenon previously described for maintaining primordial germ cells (PGCs) in a quiescent state. Specifically, they show erasure of parental imprinting at the Igf2-H19 locus, which keeps them in a quiescent state in a similar manner as migrating PGCs. To date, the presence of these cells in adult postnatal tissues have been demonstrated by at least 25 independent laboratories. We envision that similar changes in expression of parentally imprinted genes may also play a role in the quiescence of dormant VSELs present in other non-hematopoietic tissues. Recent data indicate that VSELs expand and after reestablishment of somatic imprinting at the Igf2-H19 locus by nicotinamide treatment in response to stimulation by pituitary gonadotrophins (follicle stimulating factor, luteinizing hormone and prolactin) and gonadal androgens and estrogens. These cells could be also successfully expanded in the presence of the small molecule UM177.
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J Am Chem Soc
January 2025
School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore.
Photodynamic therapy (PDT) holds promise as a cancer treatment modality due to its potential for enhanced therapy precision and safety. To enhance deep tissue penetration and minimize tissue adsorption and phototoxicity, developing photosensitizers activated by second near-infrared window (NIR-II) light shows significant potential. However, the efficacy of PDT is often impeded by tumor microenvironment hypoxia, primarily caused by irregular tumor vasculature.
View Article and Find Full Text PDFHum Reprod Update
January 2025
Amsterdam UMC, Location Vrije Universiteit Amsterdam, Centre of Expertise on Gender Dysphoria, Amsterdam, The Netherlands.
Background: Transgender and gender diverse (TGD) people seek gender-affirming care at any age to manage gender identities or expressions that differ from their birth gender. Gender-affirming hormone treatment (GAHT) and gender-affirming surgery may alter reproductive function and/or anatomy, limiting future reproductive options to varying degrees, if individuals desire to either give birth or become a biological parent.
Objective And Rationale: TGD people increasingly pursue help for their reproductive questions, including fertility, fertility preservation, active desire for children, and future options.
Sci Adv
January 2025
Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA, USA.
Oxygen controls most metazoan metabolism, yet in mammals, tissue O levels vary widely. While extensive research has explored cellular responses to hypoxia, understanding how cells respond to physiologically high O levels remains uncertain. To address this problem, we investigated respiratory epithelia as their contact with air exposes them to some of the highest O levels in the body.
View Article and Find Full Text PDFPLoS One
January 2025
Department of Surgical Pathology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
Immunologic bile duct destruction is a pathogenic condition associated with vanishing bile duct syndrome (VBDS) after liver transplantation and hematopoietic stem-cell transplantation. As the bile acid receptor sphingosine 1-phosphate receptor 2 (S1PR2) plays a critical role in recruitment of bone marrow-derived monocytes/macrophages to sites of cholestatic liver injury, S1PR2 expression was examined using cultured macrophages and patient tissues. Bile canaliculi destruction precedes intrahepatic ductopenia; therefore, we focused on hepatocyte S1PR2 and the downstream RhoA/Rho kinase 1 (ROCK1) signaling pathway and bile canaliculi alterations using three-dimensional hepatocyte culture models that form obvious bile canaliculus-like networks.
View Article and Find Full Text PDFPLoS One
January 2025
School of Clinical Medicine, Guizhou Medical University, Guiyang, China.
Legg-Calvé-Perthes disease (LCPD) involves femoral head osteonecrosis caused by disrupted blood supply, leading to joint deformity and early osteoarthritis. This study investigates the role of miRNA-223-5p in regulating hypoxia-induced apoptosis and enhancing osteogenesis in bone marrow mesenchymal stem cells (BMSCs). Utilizing a juvenile New Zealand white rabbit model of LCPD established through femoral neck ligation, we transfected BMSCs with miR-223-5p mimics, inhibitors, and controls, followed by hypoxic exposure.
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