Characterisation and hierarchy of the spermatogonial stem cell compartment in human spermatogenesis by spectral cytometry using a 16-colors panel.

About one in six couples experience fertility problems, and male infertility accounts for about half of these cases. Spermatogenesis originates from a small pool of spermatogonial stem cells (SSCs), which are of interest for the treatment of infertility but remain poorly characterised in humans. Using multiparametric spectral flow cytometric analysis with a 16-colours (16-C) panel of cell markers, we identify novel markers of SSCs and provide insights into unravelling and resolving the heterogeneity of the human spermatogonial cells.

Dystrophin deficiency impairs cell junction formation during embryonic myogenesis from pluripotent stem cells.

Mutations in the gene lead to Duchenne muscular dystrophy (DMD), a severe neuromuscular disorder affecting young boys as they acquire motor functions. DMD is typically diagnosed at 2-4 years of age, but the absence of dystrophin has negative impacts on skeletal muscles before overt symptoms appear in patients, which poses a serious challenge in current standards of care. Here, we investigated the consequences of dystrophin deficiency during skeletal muscle development.

Generation of heterozygous and homozygous NF1 lines from human-induced pluripotent stem cells using CRISPR/Cas9 to investigate bone defects associated with neurofibromatosis type 1.

Neurofibromatosis type 1 (NF1) is one of the most common genetic disorders caused by heterozygous germline mutations. NF1 affects many systems, including the skeletal system. To date, no curative therapies are available for skeletal manifestations such as scoliosis and tibial dysplasia, mainly due to the lack of knowledge about the mechanisms that underlie this process.

Mono- and Biallelic Inactivation of Huntingtin Gene in Patient-Specific Induced Pluripotent Stem Cells Reveal HTT Roles in Striatal Development and Neuronal Functions.

Background: Mutations in the Huntingtin (HTT) gene cause Huntington's disease (HD), a neurodegenerative disorder. As a scaffold protein, HTT is involved in numerous cellular functions, but its normal and pathogenic functions during human forebrain development are poorly understood.

Objective: To investigate the developmental component of HD, with a specific emphasis on understanding the functions of wild-type and mutant HTT alleles during forebrain neuron development in individuals carrying HD mutations.

Dystrophin deficiency impairs cell junction formation during embryonic myogenesis.

Mutations in the gene lead to Duchenne muscular dystrophy, a severe X-linked neuromuscular disorder that manifests itself as young boys acquire motor functions. DMD is typically diagnosed at 2 to 4 years of age, but the absence of dystrophin negatively impacts muscle structure and function before overt symptoms appear in patients, which poses a serious challenge in the optimization of standards of care. In this report, we investigated the early consequences of dystrophin deficiency during skeletal muscle development.

Advances in the engineering of the outer blood-retina barrier: From in-vitro modelling to cellular therapy.

The outer blood-retina barrier (oBRB), crucial for the survival and the proper functioning of the overlying retinal layers, is disrupted in numerous diseases affecting the retina, leading to the loss of the photoreceptors and ultimately of vision. To study the oBRB and/or its degeneration, many oBRB models have been developed, notably to investigate potential therapeutic strategies against retinal diseases. Indeed, to this day, most of these pathologies are untreatable, especially once the first signs of degeneration are observed.

Semi-automated optimized method to isolate CRISPR/Cas9 edited human pluripotent stem cell clones.

Background: CRISPR/Cas9 editing systems are currently used to generate mutations in a particular gene to mimic a genetic disorder in vitro. Such "disease in a dish" models based on human pluripotent stem cells (hPSCs) offer the opportunity to have access to virtually all cell types of the human body. However, the generation of mutated hPSCs remains fastidious.

Generating Functional and Highly Proliferative Melanocytes Derived from Human Pluripotent Stem Cells: A Promising Tool for Biotherapeutic Approaches to Treat Skin Pigmentation Disorders.

Melanocytes are essential for skin homeostasis and protection, and their loss or misfunction leads to a wide spectrum of diseases. Cell therapy utilizing autologous melanocytes has been used for years as an adjunct treatment for hypopigmentary disorders such as vitiligo. However, these approaches are hindered by the poor proliferative capacity of melanocytes obtained from skin biopsies.

Photoreceptor Cell Replacement Using Pluripotent Stem Cells: Current Knowledge and Remaining Questions.

Retinal degeneration is an increasing global burden without cure for the majority of patients. Once retinal cells have degenerated, vision is permanently lost. Different strategies have been developed in recent years to prevent retinal degeneration or to restore sight (e.

Clinical Grade Human Pluripotent Stem Cell-Derived Engineered Skin Substitutes Promote Keratinocytes Wound Closure In Vitro.

Chronic wounds, such as leg ulcers associated with sickle cell disease, occur as a consequence of a prolonged inflammatory phase during the healing process. They are extremely hard to heal and persist as a significant health care problem due to the absence of effective treatment and the uprising number of patients. Indeed, there is a critical need to develop novel cell- and tissue-based therapies to treat these chronic wounds.

Transcriptional profiling of β-2MSPα-6THY1 spermatogonial stem cells in human spermatogenesis.

Male infertility is responsible for approximately half of all cases of reproductive issues. Spermatogenesis originates in a small pool of spermatogonial stem cells (SSCs), which are of interest for therapy of infertility but remain not well defined in humans. Using multiparametric analysis of the side population (SP) phenotype and the α-6 integrin, THY1, and β-2 microglobulin cell markers, we identified a population of human primitive undifferentiated spermatogonia with the phenotype β-2 microglobulin (β-2M)SPα-6THY1, which is highly enriched in stem cells.

Human iPSC-derived neurons reveal early developmental alteration of neurite outgrowth in the late-occurring neurodegenerative Wolfram syndrome.

Recent studies indicate that neurodegenerative processes that appear during childhood and adolescence in individuals with Wolfram syndrome (WS) occur in addition to early brain development alteration, which is clinically silent. Underlying pathological mechanisms are still unknown. We have used induced pluripotent stem cell-derived neural cells from individuals affected by WS in order to reveal their phenotypic and molecular correlates.

Activation of HIF1α Rescues the Hypoxic Response and Reverses Metabolic Dysfunction in the Diabetic Heart.

Type 2 diabetes (T2D) impairs hypoxia-inducible factor (HIF)1α activation, a master transcription factor that drives cellular adaptation to hypoxia. Reduced activation of HIF1α contributes to the impaired post-ischemic remodeling observed following myocardial infarction in T2D. Molidustat is an HIF stabilizer currently undergoing clinical trials for the treatment of renal anemia associated with chronic kidney disease; however, it may provide a route to pharmacologically activate HIF1α in the T2D heart.

The Future of Regenerative Medicine: Cell Therapy Using Pluripotent Stem Cells and Acellular Therapies Based on Extracellular Vesicles.

The rapid progress in the field of stem cell research has laid strong foundations for their use in regenerative medicine applications of injured or diseased tissues. Growing evidences indicate that some observed therapeutic outcomes of stem cell-based therapy are due to paracrine effects rather than long-term engraftment and survival of transplanted cells. Given their ability to cross biological barriers and mediate intercellular information transfer of bioactive molecules, extracellular vesicles are being explored as potential cell-free therapeutic agents.

Hypoxia favors chemoresistance in T-ALL through an HIF1α-mediated mTORC1 inhibition loop.

Resistance to chemotherapy, a major therapeutic challenge in the treatment of T-cell acute lymphoblastic leukemia (T-ALL), can be driven by interactions between leukemic cells and the microenvironment that promote survival of leukemic cells. The bone marrow, an important leukemia niche, has low oxygen partial pressures that highly participate in the regulation of normal hematopoiesis. Here we show that hypoxia inhibits T-ALL cell growth by slowing down cell cycle progression, decreasing mitochondria activity, and increasing glycolysis, making them less sensitive to antileukemic drugs and preserving their ability to initiate leukemia after treatment.

Human pluripotent stem cells: A toolbox to understand and treat retinal degeneration.

Age-related Macular Degeneration (AMD) and Retinitis Pigmentosa (RP) are retinal degenerative disorders that dramatically damage the retina. As there is no therapeutic option for the majority of patients, vision is progressively and irremediably lost. Owing to their unlimited renewal and potency to give rise to any cell type of the human adult body, human pluripotent stem cells (hPSCs) have been extensively studied in recent years to develop more physiologically relevant in vitro cellular models.

Human erythroleukemia genetics and transcriptomes identify master transcription factors as functional disease drivers.

Acute erythroleukemia (AEL or acute myeloid leukemia [AML]-M6) is a rare but aggressive hematologic malignancy. Previous studies showed that AEL leukemic cells often carry complex karyotypes and mutations in known AML-associated oncogenes. To better define the underlying molecular mechanisms driving the erythroid phenotype, we studied a series of 33 AEL samples representing 3 genetic AEL subgroups including TP53-mutated, epigenetic regulator-mutated (eg, DNMT3A, TET2, or IDH2), and undefined cases with low mutational burden.

Contribution of Single-Cell Transcriptomics to the Characterization of Human Spermatogonial Stem Cells: Toward an Application in Male Fertility Regenerative Medicine?

Ongoing progress in genomic technologies offers exciting tools that can help to resolve transcriptome and genome-wide DNA modifications at single-cell resolution. These methods can be used to characterize individual cells within complex tissue organizations and to highlight various molecular interactions. Here, we will discuss recent advances in the definition of spermatogonial stem cells (SSC) and their progenitors in humans using the single-cell transcriptome sequencing (scRNAseq) approach.

KLF4 inhibition promotes the expansion of keratinocyte precursors from adult human skin and of embryonic-stem-cell-derived keratinocytes.

Expanded autologous skin keratinocytes are currently used in cutaneous cell therapy, and embryonic-stem-cell-derived keratinocytes could become a complementary alternative. Regardless of keratinocyte provenance, for efficient therapy it is necessary to preserve immature keratinocyte precursors during cell expansion and graft processing. Here, we show that stable and transient downregulation of the transcription factor Krüppel-like factor 4 (KLF4) in keratinocyte precursors from adult skin, using anti-KLF4 RNA interference or kenpaullone, promotes keratinocyte immaturity and keratinocyte self-renewal in vitro, and enhances the capacity for epidermal regeneration in mice.

Engineering Transplantation-suitable Retinal Pigment Epithelium Tissue Derived from Human Embryonic Stem Cells.

Several pathological conditions of the eye affect the functionality and/or the survival of the retinal pigment epithelium (RPE). These include some forms of retinitis pigmentosa (RP) and age-related macular degeneration (AMD). Cell therapy is one of the most promising therapeutic strategies proposed to cure these diseases, with already encouraging preliminary results in humans.

Autologous Haematopoietic Stem Cell Transplantation for Crohn's Disease: A Retrospective Survey of Long-term Outcomes From the European Society for Blood and Marrow Transplantation.

Background And Aims: Autologous haematopoietic stem cell transplantation [AHSCT] is a therapeutic option for patients with severe, treatment-refractory Crohn's disease [CD]. The evidence base for AHSCT for CD is limited, with one randomised trial [ASTIC] suggesting benefit. The aim of this study was to evaluate safety and efficacy for patients undergoing AHSCT for CD in Europe, outside the ASTIC trial.