Slow and steady is the key to β-cell replication

The β-cells of the pancreas are responsible for insulin production and their destruction results in type I diabetes. β-cell maintenance, growth and regenerative repair is thought to occur predominately, if not exclusively, through the replication of existing β-cells, not via an adult stem cell. It was recently found that all β-cells contribute equally to islet growth and maintenance. The fact that all β-cells replicate homogeneously makes it possible to set up straightforward screens for factors that increase β-cell replication either In vitro or in vivo . It is possible that a circulating factor may be capable of increasing β-cell replication or that intrinsic cell cycle regulators may affect β-cell growth. An improved understanding of the in vivo maintenance and growth of β-cells will facilitate efforts to expand β-cells In vitro and may lead to new treatments for diabetes.     

Understanding cell fate acquisition in stem-cell-derived pancreatic islets using single-cell multiome-inferred regulomes

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Progression of human bone marrow stromal cells into both osteogenic and adipogenic lineages is differentially regulated by structural conformation of collagen I matrix via distinct signaling pathways

Adult human bone marrow stromal cells (BMSCs) containing or consisting of mesenchymal stem cells (MSCs) are an important source in tissue homeostasis and repair. Although many processes involved in their differentiation into diverse lineages have been deciphered, substantial inroads remain to be gained to synthesize a complete regulatory picture. The present study suggests that structural conformation of extracellular collagen I, the major organic matrix component in musculoskeletal tissues, plays, along with differentiation stimuli, a decisive role in the selection of differentiation lineage. It introduces a novel concept which proposes that structural transition of collagen I matrix regulates cell differentiation through distinct signaling pathways specific for the structural state of the matrix. Thus, on native collagen I matrix inefficient adipogenesis is p38-independent, whereas on its denatured counterpart, an efficient adipogenesis is primarily regulated by p38 kinase. Inversely, osteogenic differentiation occurs efficiently on native, but not on denatured collagen I matrix, with a low commencement threshold on the former and a substantially higher one on the latter. Osteogenesis on collagen I matrices in both structural conformations is fully dependent on ERK. However, whereas on native collagen I matrix osteogenic differentiation is Hsp90-dependent, on denatured collagen I matrix it is Hsp90-independent. The matrix conformation-mediated regulation appears to be one of the mechanisms determining differentiation lineage of BMSCs. It allows a novel interpretation of the bone remodeling cycle, explains the marked physiological aging-related adipogenic shift in musculoskeletal tissues, and can be a principal contributor to adipogenic shift seen in a number of clinical disorders.     

Bioengineering Considerations for a Nurturing Way to Enhance Scalable Expansion of Human Pluripotent Stem Cells

Understanding how defects in mechanotransduction affect cell‐to‐cell variability will add to the fundamental knowledge of human pluripotent stem cell (hPSC) culture, and may suggest new approaches for achieving a robust, reproducible, and scalable process that result in consistent product quality and yields. Here, the current state of the understanding of the fundamental mechanisms that govern the growth kinetics of hPSCs between static and dynamic cultures is reviewed, the factors causing fluctuations are identified, and culture strategies that might eliminate or minimize the occurrence of cell‐to‐cell variability arising from these fluctuations are discussed. The existing challenges in the development of hPSC expansion methods for enabling the transition from process development to large‐scale production are addressed, a mandatory step for industrial and clinical applications of hPSCs.     

Amniotic fluid stem cells to study mTOR signaling in differentiation

The protein kinase mTOR is the central player within a pathway, which is known to be involved in the regulation of e.g., cell size, cell cycle, apoptosis, autophagy, aging and differentiation. mTOR activity responds to many signals, including cellular stress, oxygen, nutrient availability, energy status and growth factors. Deregulation of this enzyme is causatively involved in the molecular development of monogenic human diseases, cancer, obesity, type 2 diabetes or neurodegeneration. Recently, mTOR has also been demonstrated to control stem cell homeostasis. A more detailed investigation of this new mTOR function will be of highest relevance to provide more explicit insights into stem cell regulation in the near future. Different cellular tools, including adult stem cells, embryonic stem cells or induced pluripotent stem cells could be used to investigate the role of mTOR in mammalian stem cell biology. Here we discuss the potential of amniotic fluid stem cells to become a promising cellular model to study the role of signaling cascades in stem cell homeostasis.     

Assessment of plant secondary metabolites in oil palm seedlings after being treated with calcium,copper ions and salicylic acid

The effect of calcium, copper ions and salicylic acid (SA) amendment on the incidence of basal stem rot and activity of secondary metabolites in oil palm seedlings were investigated in glasshouse study. Disease incidence (DI) in positive control (T8) was 75% at nine months after inoculation (9 MAI). However, weekly pre-immunisation with Ca^2+?+^?Cu^2+?+^?SA prior to inoculation significantly suppressed DI and delayed disease onset as noted in T7. In the present study, the lowest %DI was observed in T7 (15%) followed by T1, T5, T6, T3, T4 and T2. The Ca²⁺, Cu²⁺ and SA amendments were resulted in earlier and higher accumulation of plant secondary metabolites as noted in leaves, stems and root tissues in response to invasion by Ganoderma boninense. High total phenolic content concentration was detected in T7 (leaf: 233.38 ± 0.12 mg/g; stem: 132.78 ± 0.04 mg/g and root: 86.98 ± 0.28 mg/g). Similar trend was obtained in peroxidase activity, total lignin content and hydrogen peroxide scavenging activity. These results suggested that it could be due to the accumulation of phenolics, peroxidase activities, lignin content and hydrogen peroxide scavenging activities in oil palm seedling tissues which might have collectively contributed to induce resistance against G. boninense.