Regeneration of immunocompetent B lymphopoiesis from pluripotent stem cells guided by transcription factors

Increased CD56 expression after photodynamic therapy indicates an increased natural killer cell count following early photodynamic therapy for cutaneous squamous cell carcinoma

Cutaneous squamous cell carcinoma (cSCC) is the second most common type of skin cancer. Photodynamic therapy (PDT) is a promising therapeutic method for managing cSCC due to its proven ability to target specific areas over time and its low risk of side effects. PDT may cause tissue damage and vascular shutdown, and may regulate local immunological responses. The present study aimed to investigate and compare the early lymphocyte modifications before and after PDT for SCC. A total of 10 patients with SCC were identified by pathological investigation. Initially, all wounds were treated with 20% aminolevulinic acid (ALA)-PDT as the initial stage in the therapeutic procedure. The wounds were treated by exposing them to red LED light with a wavelength of 635 nm, an energy density of 100 J/cm2 and an intensity of 80 mW/cm2. The tumor tissue was surgically removed 24 h later, and another round of PDT therapy was administered. Immunohistochemistry for CD3 and CD56 was conducted on the wound tissue post-surgery. If the wound showed granulation, necrosis or secretion, debridement was added to the therapy. All patients were monitored for 0.6-1.0 year post-treatment. ALA-PDT combination surgery fully controlled the tumor tissue in all 10 patients. The immunohistochemical analysis of the wound tissues showed that the expression of CD56 increased, while the expression of CD3 was not different after photodynamic therapy. These results also indirectly indicated that the overall count of NK cells in the 10 patients increased, nevertheless, there was no alteration in the T lymphocyte count. In conclusion, the ALA-PDT combination surgical therapy for cSCC demonstrates favorable results. An increase in CD56 expression may be a mechanism for the effective treatment of cSCC with PDT.

The roles of B cells in cardiovascular diseases

Damage to the heart can start the repair process and cause cardiac remodeling. B cells play an important role in this process. B cells are recruited to the injured place and activate cardiac remodeling through secreting antibodies and cytokines. Different types of B cells showed specific functions in the heart. Among all types of B cells, heart-associated B cells play a vital role in the heart by secreting TGFβ1. B cells participate in the activation of fibroblasts and promote cardiac fibrosis. Four subtypes of B cells in the heart revealed the relationship between the B cells' heterogeneity and cardiac remodeling. Many cardiovascular diseases like atherosclerosis, heart failure (HF), hypertension, myocardial infarction (MI), and dilated cardiomyopathy (DCM) are related to B cells. The primary mechanisms of these B cell-related activities will be discussed in this review, which may also suggest potential novel therapeutic targets.

The role of GATA2 in adult hematopoiesis and cell fate determination

The correct maintenance and differentiation of hematopoietic stem cells (HSC) in bone marrow is vital for the maintenance and operation of the human blood system. GATA2 plays a critical role in the maintenance of HSCs and the specification of HSCs into the different hematopoietic lineages, highlighted by the various defects observed in patients with heterozygous mutations in GATA2, resulting in cytopenias, bone marrow failure and increased chance of myeloid malignancy, termed GATA2 deficiency syndrome. Despite this, the mechanisms underlying GATA2 deficiency syndrome remain to be elucidated. The detailed description of how GATA2 regulates HSC maintenance and blood lineage determination is crucial to unravel the pathogenesis of GATA2 deficiency syndrome. In this review, we summarize current advances in elucidating the role of GATA2 in hematopoietic cell fate determination and discuss the challenges of modeling GATA2 deficiency syndrome.

Generating hematopoietic cells from human pluripotent stem cells: approaches, progress and challenges

Human pluripotent stem cells (hPSCs) have been suggested as a potential source for the production of blood cells for clinical application. In two decades, almost all types of blood cells can be successfully generated from hPSCs through various differentiated strategies. Meanwhile, with a deeper understanding of hematopoiesis, higher efficiency of generating progenitors and precursors of blood cells from hPSCs is achieved. However, how to generate large-scale mature functional cells from hPSCs for clinical use is still difficult. In this review, we summarized recent approaches that generated both hematopoietic stem cells and mature lineage cells from hPSCs, and remarked their efficiency and mechanisms in producing mature functional cells. We also discussed the major challenges in hPSC-derived products of blood cells and provided some potential solutions. Our review summarized efficient, simple, and defined methodologies for developing good manufacturing practice standards for hPSC-derived blood cells, which will facilitate the translation of these products into the clinic.

'Off the shelf' immunotherapies: Generation and application of pluripotent stem cell-derived immune cells

In recent years, great strides have been made toward the development of immune cell-based therapies in the treatment of refractory malignancies. Primary T cells and NK cells armed with chimeric antigen receptors have achieved tremendous clinical success especially in patients with leukaemia and lymphoma. However, the autologous origin of these effector cells means that a single batch of laboriously engineered cells treats only a certain patient, leading to high cost, ununiform product quality, and risk of delay in treatment, and therefore results in restricted accessibility of these therapies to the overwhelming majority of the patients. Addressing these tricky obstacles calls for the development of universal immune cell products that can be provided 'off the shelf' in a large amount. Pluripotent stem cells (PSCs), owing to their unique capacity of self-renewal and the potential of multi-lineage differentiation, offer an unlimited cell source to generate uniform and scalable engineered immune cells. This review discusses the major advances in the development of PSC-derived immune cell differentiation approaches and their therapeutic potential in treating both hematologic malignancies and solid tumours. We also consider the potency of PSC-derived immune cells as an alternative therapeutic strategy for other diseases, such as autoimmune diseases, fibrosis, infections, et al.

Prolonged generation of multi-lineage blood cells in wild-type animals from pluripotent stem cells

Regenerating prolonged multi-lineage hematopoiesis from pluripotent stem cells (PSCs), an unlimited cell source, is a crucial aim of regenerative hematology. In this study, we used a gene-edited PSC line and revealed that simultaneous expression of three transcription factors, Runx1, Hoxa9, and Hoxa10, drove the robust emergence of induced hematopoietic progenitor cells (iHPCs). The iHPCs engrafted successfully in wild-type animals and repopulated abundant and complete myeloid-, B-, and T-lineage mature cells. The generative multi-lineage hematopoiesis distributed normally in multiple organs, persisted over 6 months, and eventually declined over time with no leukemogenesis. Transcriptome characterization of generative myeloid, B, and T cells at the single-cell resolution further projected their identities to natural cell counterparts. Thus, we provide evidence that co-expression of exogenous Runx1, Hoxa9, and Hoxa10 simultaneously leads to long-term reconstitution of myeloid, B, and T lineages using PSC-derived iHPCs as the cell source.

Co-Expression of Runx1, Hoxa9, Hlf, and Hoxa7 Confers Multi-Lineage Potential on Hematopoietic Progenitors Derived From Pluripotent Stem Cells

The intrinsic factors that determine the fundamental traits of engraftment ability and multi-lineage potential of hematopoietic stem cells (HSCs) remain elusive. The induction of bona fade HSCs from pluripotent stem cells (PSCs) in dishes is urgently demanded but remains a great challenge in translational medicine. Runx1, Hoxa9, Hlf, and Hoxa7 are developmentally co-expressed during endothelial-to-hematopoietic transition and adult haematopoiesis. However, the expression of these factors fails to be turned on during in vitro hematopoietic induction from PSCs. Here, we established an inducible gene over-expression embryonic stem cell (ESC) line in which exogenous Runx1, Hoxa9, Hlf, and Hoxa7 genes were tandemly knocked in. A population of induced hematopoietic progenitor cells (iHPCs) expressing Kit and Sca1 surface markers were successfully obtained in vitro from the gene edited-ESC line. Upon transplantation of the Runx1-Hoxa9-Hlf-Hoxa7 ESC-derived iHPCs into irradiated immunodeficient mice, they can dominantly contribute to B cells, low proportions of T cells and myeloid cells. However, Runx1-Hoxa9-Hlf ESC-derived iHPCs only produced B lineage cells with extremely low contributions. Our study unveils that the coordination of Runx1, Hoxa9, Hlf, and Hoxa7 led to generation of the hematopoietic progenitors with the capacity of multi-lineage hematopoietic reconstitution in the immunodeficient recipient mice.

Hematopoietic Cells from Pluripotent Stem Cells: Hope and Promise for the Treatment of Inherited Blood Disorders

Inherited blood disorders comprise a large spectrum of diseases due to germline mutations in genes with key function in the hematopoietic system; they include immunodeficiencies, anemia or metabolic diseases. For most of them the only curative treatment is bone marrow transplantation, a procedure associated to severe complications; other therapies include red blood cell and platelet transfusions, which are dependent on donor availability. An alternative option is gene therapy, in which the wild-type form of the mutated gene is delivered into autologous hematopoietic stem cells using viral vectors. A more recent therapeutic perspective is gene correction through CRISPR/Cas9-mediated gene editing, that overcomes safety concerns due to insertional mutagenesis and allows correction of base substitutions in large size genes difficult to incorporate into vectors. However, applying this technique to genomic disorders caused by large gene deletions is challenging. Chromosomal transplantation has been proposed as a solution, using a universal source of wild-type chromosomes as donor, and induced pluripotent stem cells (iPSCs) as acceptor. One of the obstacles to be addressed for translating PSC research into clinical practice is the still unsatisfactory differentiation into transplantable hematopoietic stem or mature cells. We provide an overview of the recent progresses in this field and discuss challenges and potential of iPSC-based therapies for the treatment of inherited blood disorders.