CRISPR-Cas9 is a promising technology for genome editing. Here we use Cas9 nuclease-induced double-strand break DNA (DSB) at the UROS locus to model and correct congenital erythropoietic porphyria. ...We demonstrate that homology-directed repair is rare compared with NHEJ pathway leading to on-target indels and causing unwanted dysfunctional protein. Moreover, we describe unexpected chromosomal truncations resulting from only one Cas9 nuclease-induced DSB in cell lines and primary cells by a p53-dependent mechanism. Altogether, these side effects may limit the promising perspectives of the CRISPR-Cas9 nuclease system for disease modeling and gene therapy. We show that the single nickase approach could be safer since it prevents on- and off-target indels and chromosomal truncations. These results demonstrate that the single nickase and not the nuclease approach is preferable, not only for modeling disease but also and more importantly for the safe management of future CRISPR-Cas9-mediated gene therapies.
The aim of this paper is to provide a theoretical framework to understand how multicellular systems realize functionally integrated physiological entities by organizing their intercellular space. ...From a perspective centered on physiology and integration, biological systems are often characterized as organized in such a way that they realize metabolic self-production and self-maintenance. The existence and activity of their components rely on the network they realize and on the continuous management of the exchange of matter and energy with their environment. One of the virtues of the organismic approach focused on organization is that it can provide an understanding of how biological systems are functionally integrated into coherent wholes. Organismic frameworks have been primarily developed by focusing on unicellular life. Multicellularity, however, presents additional challenges to our understanding of biological systems, related to how cells are capable to live together in higher-order entities, in such a way that some of their features and behaviors are constrained and controlled by the system they realize. Whereas most accounts of multicellularity focus on cell differentiation and increase in size as the main elements to understand biological systems at this level of organization, we argue that these factors are insufficient to provide an understanding of how cells are physically and functionally integrated in a coherent system. In this paper, we provide a new theoretical framework to understand multicellularity, capable to overcome these issues. Our thesis is that one of the fundamental theoretical principles to understand multicellularity, which is missing or underdeveloped in current accounts, is the functional organization of the intercellular space. In our view, the capability to be organized in space plays a central role in this context, as it enables (and allows to exploit all the implications of) cell differentiation and increase in size, and even specialized functions such as immunity. We argue that the extracellular matrix plays a crucial active role in this respect, as an evolutionary ancient and specific (non-cellular) control subsystem that contributes as a key actor to the functional specification of the multicellular space and to modulate cell fate and behavior. We also analyze how multicellular systems exert control upon internal movement and communication. Finally, we show how the organization of space is involved in some of the failures of multicellular organization, such as aging and cancer.The aim of this paper is to provide a theoretical framework to understand how multicellular systems realize functionally integrated physiological entities by organizing their intercellular space. From a perspective centered on physiology and integration, biological systems are often characterized as organized in such a way that they realize metabolic self-production and self-maintenance. The existence and activity of their components rely on the network they realize and on the continuous management of the exchange of matter and energy with their environment. One of the virtues of the organismic approach focused on organization is that it can provide an understanding of how biological systems are functionally integrated into coherent wholes. Organismic frameworks have been primarily developed by focusing on unicellular life. Multicellularity, however, presents additional challenges to our understanding of biological systems, related to how cells are capable to live together in higher-order entities, in such a way that some of their features and behaviors are constrained and controlled by the system they realize. Whereas most accounts of multicellularity focus on cell differentiation and increase in size as the main elements to understand biological systems at this level of organization, we argue that these factors are insufficient to provide an understanding of how cells are physically and functionally integrated in a coherent system. In this paper, we provide a new theoretical framework to understand multicellularity, capable to overcome these issues. Our thesis is that one of the fundamental theoretical principles to understand multicellularity, which is missing or underdeveloped in current accounts, is the functional organization of the intercellular space. In our view, the capability to be organized in space plays a central role in this context, as it enables (and allows to exploit all the implications of) cell differentiation and increase in size, and even specialized functions such as immunity. We argue that the extracellular matrix plays a crucial active role in this respect, as an evolutionary ancient and specific (non-cellular) control subsystem that contributes as a key actor to the functional specification of the multicellular space and to modulate cell fate and behavior. We also analyze how multicellular systems exert control upon internal movement and communication. Finally, we show how the organization of space is involved in some of the failures of multicellular organization, such as aging and cancer.
Low-grade, chronic inflammation has been associated with many diseases of aging, but the mechanisms responsible for producing this inflammation remain unclear. Inflammasomes can drive chronic ...inflammation in the context of an infectious disease or cellular stress, and they trigger the maturation of interleukin-1β (IL-1β). Here we find that the expression of specific inflammasome gene modules stratifies older individuals into two extremes: those with constitutive expression of IL-1β, nucleotide metabolism dysfunction, elevated oxidative stress, high rates of hypertension and arterial stiffness; and those without constitutive expression of IL-1β, who lack these characteristics. Adenine and N
-acetylcytidine, nucleotide-derived metabolites that are detectable in the blood of the former group, prime and activate the NLRC4 inflammasome, induce the production of IL-1β, activate platelets and neutrophils and elevate blood pressure in mice. In individuals over 85 years of age, the elevated expression of inflammasome gene modules was associated with all-cause mortality. Thus, targeting inflammasome components may ameliorate chronic inflammation and various other age-associated conditions.
This article draws on the theory of disruption to analyze the impact of digital technology on the recorded music industry and to explain the delay of dominant firms in reacting to this technological ...discontinuity. The author shows that digitization matches the characteristics of disruptive innovation as described in the literature. He explains why established firms initially paid little heed to an innovation leading to a product (digital music files) that is cheaper and poorer in quality than their existing product (CDs) and ill-suited to mainstream consumers. The reaction of these firms has been typical of the behaviour of companies facing disruptive innovation. Confronted with an innovation that they see as more of a threat than an opportunity, incumbent firms have found it extremely difficult to accept the need for a radical rethinking of their business model. Cet article s'appuie sur la théorie de la rupture pour analyser l'impact de la technologie numérique sur l'industrie de la musique enregistrée et expliquer le retard pris par les firmes dominantes pour s'adapter à cette discontinuité technologique. Il montre tout d'abord que la technologie numérique présente les caractéristiques d'une innovation de rupture telles qu'elles sont décrites dans la littérature. L'auteur explique également pourquoi les principales maisons de disques ont initialement considéré comme peu attrayante une innovation qui conduisait à un produit (les fichiers numériques musicaux) moins cher et de moins bonne qualité que le produit existant (les CD) et de surcroît peu adapté à leurs consommateurs principaux. La réaction de ces firmes a été caractéristique du comportement d'entreprises confrontées à une innovation de rupture. Face à une innovation qu'elles considéraient plus comme une menace que comme une opportunité, les firmes en place se sont révélées très réticentes à accepter une profonde remise en cause de leur modèle d'affaires. Este artículo se apoya en la teoría disruptiva para analizar el impacto de la tecnología digital sobre la industria discográfica y explicar el retraso de las empresas dominantes en adaptarse a esta discontinuidad tecnológica. En primer lugar, se demuestra que la tecnología digital presenta las características de una innovación disruptiva tal como descrita en las publicaciones existentes. El autor también explica porqué las principales compañías disqueras en un principio vieron como poco atractiva una innovación que llevaba a un producto (los archivos de música digital) de menor costo y de menos calidad que el producto existente (los CD) y además mal adaptado a sus consumidores principales. La reacción de estas compañías fue característica del comportamiento de las empresas que se ven ante una innovación disruptiva, ante una innovación que consideran más bien una amenaza que una oportunidad. Las compañías existentes han mostrado una gran renuencia a aceptar un profundo cuestionamiento de su modelo comercial.
Using weekly music charts data in 10 countries over the period 1990–2015, we analyze whether digitization leads to a trend of homogenization of music content or conversely to a greater acoustic ...disparity. We split the digitization era in four periods that correspond to four new emblematic distribution models (Napster, iTunes, YouTube, Spotify). Our main result is that while acoustic diversity decreased during the iTunes and the YouTube periods, the period that begins with the introduction of audio streaming services, such as Spotify, represents a turning point and is marked by a significant increase in acoustic diversity.
Mueller polarimetric imaging enables the detection and quantification of modifications of the collagen fibers in the uterine cervix due to the development of a precancerous lesion. This information ...is not accessible through the use of the classic colposcope, a low magnification microscope used in current practice for cervical cancer screening. However, the in vivo application of Mueller polarimetric imaging poses an instrumental challenge: the device should be sufficiently compact, while still being able to perform fast and accurate acquisition of Mueller matrices in real-world conditions. In this study, the first wide field Mueller Polarimetric Colposcope (MPC) for the in vivo analysis of uterine cervix is presented. The MPC has been fabricated by grafting a miniaturized Mueller polarimetric imager on a classic colposcope. This new imaging tool performs the fast acquisition of Mueller polarimetric images, thus eliminating any blurring effects due to patient movements. It can be easily used by a practitioner with little change to their existing practice. Finally, the MPC was tested in vivo on a number of patients in the field.
The presence of circulating tumor cells (CTCs) and CTC clusters, also known as tumor microemboli, in biological fluids has long been described. Intensive research on single CTCs has made a ...significant contribution in understanding tumor invasion, metastasis tropism, and intra-tumor heterogeneity. Moreover, their being minimally invasive biomarkers has positioned them for diagnosis, prognosis, and recurrence monitoring tools. Initially, CTC clusters were out of focus, but major recent advances in the knowledge of their biogenesis and dissemination reposition them as critical actors in the pathophysiology of cancer, especially metastasis. Increasing evidence suggests that "united" CTCs, organized in clusters, resist better and carry stronger metastatic capacities than "divided" single CTCs. This review gathers recent insight on CTC cluster origin and dissemination. We will focus on their distinct molecular package necessary to resist multiple cell deaths that all circulating cells normally face. We will describe the molecular basis of their increased metastatic potential as compared to single CTCs. We will consider their clinical relevance as prognostic biomarkers. Finally, we will propose future directions for research and clinical applications in this promising topic in cancer.
Increased activity of T follicular helper (Tfh) cells plays a major pathogenic role in systemic lupus erythematosus (SLE). However, the mechanisms that cause aberrant Tfh cell responses in SLE remain ...elusive. Here we showed the OX40 ligand (OX40L)-OX40 axis contributes to the aberrant Tfh response in SLE. OX40L was expressed by myeloid antigen-presenting cells (APCs), but not B cells, in blood and in inflamed tissues in adult and pediatric SLE patients. The frequency of circulating OX40L-expressing myeloid APCs positively correlated with disease activity and the frequency of ICOS+ blood Tfh cells in SLE. OX40 signals promoted naive and memory CD4+ T cells to express multiple Tfh cell molecules and were sufficient to induce them to become functional B cell helpers. Immune complexes containing RNA induced OX40L expression on myeloid APCs via TLR7 activation. Our study provides a rationale to target the OX40L-OX40 axis as a therapeutic modality for SLE.
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•OX40L is expressed by myeloid antigen-presenting cells in patients with active SLE•OX40 signals promote the differentiation of human Th cells toward the Tfh lineage•Strong TCR signals promote the expression of Tfh molecules by human Th cells•RNP-Anti-RNP immune complexes induce monocytes to express OX40L via TLR7
Although increased activity of T follicular helper (Tfh) cells plays a pathogenic role in systemic lupus erythematosus (SLE), the mechanism has been unclear. Ueno and colleagues show that exaggerated OX40 signals promote the generation of Tfh cells in SLE.
Purpose
About 25% of patients with common variable immunodeficiency disease (CVID) have splenomegaly, necessitating sometimes splenectomy whom consequences on the immunological profile of CVID ...patients have never been studied. We analyzed 11 CVID patients’ comprehensive blood immune cell phenotypes pre- and post-splenectomy.
Methods
Flow cytometry analyses of immune cell populations.
Results
Among 89 CVID cohort patients, 41 with splenomegaly, splenomegaly was strongly associated with granulomatous disease, autoimmune disorders, lymphoid hyperplasia, and/or portal hypertension. CVID patients with splenomegaly have significant peripheral lymphopenia (
p
= 0.001), and significantly fewer peripheral class-switched memory B cells (smBs) (
p
= 0.001), CD4
+
T lymphocytes (
p
= 0.001), NK (
p
= 0.0001) and dendritic cells (
p
≤ 0.01), and significantly more circulating CD4
+
and CD8
+
(
p
= 0.00001) T cell subset activation (
p
= 0.00005), than CVID patients without splenomegaly. Examination of splenectomy impact on circulating lymphocyte subset distributions demonstrated the drastically enhanced total circulating lymphocyte count post-splenectomy, predominantly B lymphocytes and CD8
+
T cells. However, splenectomy did not change B cell distribution, with smBs remaining persistently low, in contrast to complete inversion of the circulating T cell composition, with reversal of the CD4
+
/CD8
+
ratio suggesting that amplification of the CD8
+
T cell compartment is a CVID characteristic in patients with splenomegaly. Our results highlight this CD8
+
amplification in CVID–splenomegaly patients that might be explained by a homing effect to the spleen and/or possible chronic virus replication, which in turn could induce T cell expansions.
Conclusion
Splenectomizing CVID patients with splenomegaly restores the absolute circulating lymphocyte count, suggesting that the decreased T cell count in the presence of splenomegaly cannot be used as an exclusive criterion for combined immunodeficiency.
The literature is rather inconclusive when it comes to asserting whether digital technologies tend to favor collaboration (Do-It-Together, DIT) or creating alone (Do-It-Yourself, DIY) in creative ...production. In this paper, we argue that providing an answer to that question implies adopting a micro-perspective, which ties individual creators’ usage of different types of digital technologies, and their choices of DIT or DIY. Using data from a sample of French musicians, we find that while the use of some digital technologies is clearly associated with artists creating alone, other digital technologies have a more ambiguous association with DIY or DIT. We then uncover the boundary conditions of the association of these ambiguous technologies with DIY and DIT behaviors by showing how individual characteristics of the creators moderate this association.
•Digital technologies enable both collaboration (Do-It-Together), and individualism (Do-It-Yourself) in creative production.•Distinguishing the substitution and information effects associated with different digital technologies matters.•Substitution effect is associated with DIY, information effect favors both DIY and DIT.•Individual features (age, reputation and breadth of talent) affect the use of digital information tools for either DIY or DIT.
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