Screening of a Microbial Culture Collection: Empowering Selection of Starters for Enhanced Sensory Attributes of Pea-Protein-Based Beverages.

Pea-protein-based ingredients are gaining attention in the food industry due to their nutritional benefits and versatility, but their bitter, astringent, green, and beany off-flavors pose challenges. This study applied fermentation using microbial cultures to enhance the sensory qualities of pea-protein-based beverages. Using UHPLC-TOF-MS analyses along with sensory profile comparisons, microbial species such as Limosilactobacillus fermentum, Lactococcus lactis, Lactobacillus johnsonii, Lacticaseibacillus rhamnosus, and Bifidobacterium longum were preselected from an entire culture collection and found to be effective in improving the overall flavor impression by reducing bitter off-notes and enhancing aroma profiles. Notably, L. johnsonii NCC533 and L. fermentum NCC660 exhibited controlled proteolytic activities after 48 h of fermentation, enriching the matrix with taste-active amino acids, nucleotides, and peptides and improving umami and salty flavors while mitigating bitterness. This study has extended traditional volatile analyses, including nonvolatile metabolomic, proteomic, and sensory analyses and offering a detailed view of fermentation-induced biotransformations in pea-protein-based food. The results highlight the importance of combining comprehensive screening approaches and sensoproteomic techniques in developing tastier and more palatable plant-based protein products.

An engineered multicellular stem cell niche for the 3D derivation of human myogenic progenitors from iPSCs.

Fate decisions in the embryo are controlled by a plethora of microenvironmental interactions in a three-dimensional niche. To investigate whether aspects of this microenvironmental complexity can be engineered to direct myogenic human-induced pluripotent stem cell (hiPSC) differentiation, we here screened murine cell types present in the developmental or adult stem cell niche in heterotypic suspension embryoids. We identified embryonic endothelial cells and fibroblasts as highly permissive for myogenic specification of hiPSCs. After two weeks of sequential Wnt and FGF pathway induction, these three-component embryoids are enriched in Pax7-positive embryonic-like myogenic progenitors that can be isolated by flow cytometry. Myogenic differentiation of hiPSCs in heterotypic embryoids relies on a specialized structural microenvironment and depends on MAPK, PI3K/AKT, and Notch signaling. After transplantation in a mouse model of Duchenne muscular dystrophy, embryonic-like myogenic progenitors repopulate the stem cell niche, reactivate after repeated injury, and, compared to adult human myoblasts, display enhanced fusion and lead to increased muscle function. Altogether, we provide a two-week protocol for efficient and scalable suspension-based 3D derivation of Pax7-positive myogenic progenitors from hiPSCs.

In vivo transcriptomic profiling using cell encapsulation identifies effector pathways of systemic aging.

Sustained exposure to a young systemic environment rejuvenates aged organisms and promotes cellular function. However, due to the intrinsic complexity of tissues it remains challenging to pinpoint niche-independent effects of circulating factors on specific cell populations. Here, we describe a method for the encapsulation of human and mouse skeletal muscle progenitors in diffusible polyethersulfone hollow fiber capsules that can be used to profile systemic aging in vivo independent of heterogeneous short-range tissue interactions. We observed that circulating long-range signaling factors in the old systemic environment lead to an activation of Myc and E2F transcription factors, induce senescence, and suppress myogenic differentiation. Importantly, in vitro profiling using young and old serum in 2D culture does not capture all pathways deregulated in encapsulated cells in aged mice. Thus, in vivo transcriptomic profiling using cell encapsulation allows for the characterization of effector pathways of systemic aging with unparalleled accuracy.

Macroencapsulated Human iPSC-Derived Pancreatic Progenitors Protect against STZ-Induced Hyperglycemia in Mice.

In type 1 diabetes, a renewable source of human pancreatic ß cells, in particular from human induced pluripotent stem cell (hiPSC) origin, would greatly benefit cell therapy. Earlier work showed that pancreatic progenitors differentiated from human embryonic stem cells in vitro can further mature to become glucose responsive following macroencapsulation and transplantation in mice. Here we took a similar approach optimizing the generation of pancreatic progenitors from hiPSCs. This work demonstrates that hiPSCs differentiated to pancreatic endoderm in vitro can be efficiently and robustly generated under large-scale conditions. The hiPSC-derived pancreatic endoderm cells (HiPECs) can further differentiate into glucose-responsive islet-like cells following macroencapsulation and in vivo implantation. The HiPECs can protect mice from streptozotocin-induced hyperglycemia and maintain normal glucose homeostasis and equilibrated plasma glucose concentrations at levels similar to the human set point. These results further validate the potential use of hiPSC-derived islet cells for application in clinical settings.

Concise reviews: In vitro-produced pancreas organogenesis models in three dimensions: self-organization from few stem cells or progenitors.

Three-dimensional models of organ biogenesis have recently flourished. They promote a balance between stem/progenitor cell expansion and differentiation without the constraints of flat tissue culture vessels, allowing for autonomous self-organization of cells. Such models allow the formation of miniature organs in a dish and are emerging for the pancreas, starting from embryonic progenitors and adult cells. This review focuses on the currently available systems and how these allow new types of questions to be addressed. We discuss the expected advancements including their potential to study human pancreas development and function as well as to develop diabetes models and therapeutic cells.

In vitro pancreas organogenesis from dispersed mouse embryonic progenitors.

The pancreas is an essential organ that regulates glucose homeostasis and secretes digestive enzymes. Research on pancreas embryogenesis has led to the development of protocols to produce pancreatic cells from stem cells (1). The whole embryonic organ can be cultured at multiple stages of development (2-4). These culture methods have been useful to test drugs and to image developmental processes. However the expansion of the organ is very limited and morphogenesis is not faithfully recapitulated since the organ flattens. We propose three-dimensional (3D) culture conditions that enable the efficient expansion of dissociated mouse embryonic pancreatic progenitors. By manipulating the composition of the culture medium it is possible to generate either hollow spheres, mainly composed of pancreatic progenitors expanding in their initial state, or, complex organoids which progress to more mature expanding progenitors and differentiate into endocrine, acinar and ductal cells and which spontaneously self-organize to resemble the embryonic pancreas. We show here that the in vitro process recapitulates many aspects of natural pancreas development. This culture system is suitable to investigate how cells cooperate to form an organ by reducing its initial complexity to few progenitors. It is a model that reproduces the 3D architecture of the pancreas and that is therefore useful to study morphogenesis, including polarization of epithelial structures and branching. It is also appropriate to assess the response to mechanical cues of the niche such as stiffness and the effects on cell´s tensegrity.

Artificial three-dimensional niches deconstruct pancreas development in vitro.

In the context of a cellular therapy for diabetes, methods for pancreatic progenitor expansion and subsequent differentiation into insulin-producing beta cells would be extremely valuable. Here we establish three-dimensional culture conditions in Matrigel that enable the efficient expansion of dissociated mouse embryonic pancreatic progenitors. By manipulating the medium composition we generate either hollow spheres, which are mainly composed of pancreatic progenitors, or complex organoids that spontaneously undergo pancreatic morphogenesis and differentiation. The in vitro maintenance and expansion of pancreatic progenitors require active Notch and FGF signaling, thus recapitulating in vivo niche signaling interactions. Our experiments reveal new aspects of pancreas development, such as a community effect by which small groups of cells better maintain progenitor properties and expand more efficiently than isolated cells, as well as the requirement for three-dimensionality. Finally, growth conditions in chemically defined biomaterials pave the way for testing the biophysical and biochemical properties of the niche that sustains pancreatic progenitors.