Cells

Loss-of-function mutations in the ABCA4 gene cause Stargardt disease (STGD1), the most common inherited macular dystrophy leading to progressive central vision loss. Here, we generated hiPSC-derived retinal organoids harboring a premature stop codon in exon-24 of ABCA4 to evaluate the impact of this mutation on mRNA and protein levels in a human model. Immunofluorescence analysis revealed the absence of ABCA4 protein in the mutant photoreceptor outer segment discs, while single-cell RNA sequencing detected no major transcriptional alterations in rods and cones. Unexpectedly, differential gene expression and pathway enrichment analyses of Muller glial cells (MGCs) and astrocytes highlighted disruption of neuronal development, microenvironment of glial cells, intercellular communication, and programmed cell death pathways. These findings suggest that ABCA4 might play a role in maintaining the retinal microenvironment homeostasis, and that the early transcriptomic response of MGCs and astrocytes preceding photoreceptor degeneration could contribute to Stargardt disease development. Significance StatementHuman induced pluripotent stem cell (hiPSC)-derived retinal organoids provide a powerful platform to investigate inherited retinal diseases. In this study, we generated ABCA4-mutant hiPSC lines and differentiated them into retinal organoids to model Stargardt disease. Despite complete loss of ABCA4 protein from the photoreceptor outer segment discs, rods and cones exhibited minimal transcriptional alterations. In contrast, the ABCA4 variant triggered changes in the glial cell homeostasis, suggesting that Muller glial cells and astrocytes might exhibit an early response to photoreceptor dysfunction in the absence of ABCA4. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=139 SRC="FIGDIR/small/718110v1_ufig1.gif" ALT="Figure 1"> View larger version (15K): org.highwire.dtl.DTLVardef@1d8dbf6org.highwire.dtl.DTLVardef@51239corg.highwire.dtl.DTLVardef@f8fbdborg.highwire.dtl.DTLVardef@5f0b44_HPS_FORMAT_FIGEXP M_FIG Human induced pluripotent stem cells (hiPSCs) were engineered to generate ABCA4-mutant cell lines, later differentiated into retinal organoids as a model of Stargardt disease. The organoids showed loss of ABCA4 from the outer segment discs of rod and cone photoreceptors, while the mutant Muller glial cells and astrocytes exhibited transcriptional changes in pathways involved in neuronal development, microenvironment, and programmed cell death. C_FIG

Bilirubin-induced neurological damage (BIND), which is also known as Kernicterus, occurs as a consequence of defects in the bilirubin conjugation machinery, thus resulting in unconjugated bilirubin (UCB) to cross the blood-brain barrier (BBB) and accumulation. Severe hyperbilirubinemia can be caused by a mutation within the UGT1A1 encoding gene. This mutation has a direct contribution towards bilirubin conjugation leading to Kernicterus as a symptom of Crigler Najjar Syndromes (CNS1, CNS2) and Gilbert syndrome, which results in permanent neurological sequelae. In this comparative study, we used human induced pluripotent stem cells (hiPSCs)-derived 3D-brain organoids to model BIND in vitro and unveil the molecular basis of the detrimental effects of UCB in the developing human brain. hiPSC-derived from healthy and CNS patients were differentiated into day-20 brain organoids, these were then stimulated with 200nM UCB. Analyses at 24- and 72-hrs post-treatment point at UCB-induced neuro-inflammation in both cell lines. Transcriptome and associated KEGG and Gene Ontology analyses unveiled activation of distinct inflammatory pathways such as cytokine-cytokine receptor interaction, MAPK signaling, calcium signaling, NF{kappa}B activation. Furthermore, both mRNA expression and secretome analysis confirmed an upregulation of pro-inflammatory cytokines such as IL6 and IL8 upon UCB stimulation. In summary, this novel study has provided insights into how a human iPSC-derived 3D-brain organoid model can serve as a prospective platform for studying the etiology of BIND-Kernicterus.

Pathogenic variants in the X-linked gene NDP (Norrie disease protein) have been associated with a variety of non-syndromic and syndromic human retinal diseases, including Norrie disease and familial exudative vitroretinopathy. The gene codes for Norrin, a secreted angiogenic molecule which binds to FZD4 and its co-receptors LRP5/6 and TSPAN12 and activates Wnt-signaling. Additionally, it also potentiates Wnt-signaling by binding to the LGR4 receptor. Norrin was also found to exert a neuroprotective function in the retina, specifically for retinal ganglion cells. Furthermore, it was suggested to be involved in neurodevelopmental processes such as early neuro-ectodermal specification and differentiation, as well as maintenance of cochlear hair cells. To better understand the putative role of Norrin in neuronal cells of the retina we generated NDP mutant and eGFP-expressing NDP reporter human induced pluripotent stem cells, which were differentiated to retinal organoids. Bulk RNA sequencing and fixed single-cell RNA sequencing revealed alterations in gene expression as well as cellular composition, with increased proportions of retinal progenitors as well as Muller glia cells in NDPKO retinal organoids. Differential expression of genes related to glutamate signaling, Wnt and MAPK signaling, as well as neurogenesis was detected. Furthermore, genes associated with functions in the extracellular matrix were also differentially expressed. The considerable decrease in retinal neurons found in our NDPKO organoids suggest that Norrin is also important for retinal neurogenesis, which may precede the vascular manifestations in NDP-associated diseases.

Hidden collective organization of cancer cells can partially or completely return to embryoid genotype-phenotype with the plasticity to transform their morphology on cell embryoblast-like memory entities by expression of dormant genes that arise from embryogenesis. After hundreds of driver mutations, cancer cells gain new abilities or attributes and recapitulate early stages of embryogenesis. Our findings document how malignant tissues reactivated ancestral storage memory and elaborate inside tumor glands spiral- pyramidal-fractal chiral crystals (Tc) as geometric attractors proteins and biomimicry the primitive cellular blastocyst embryoblast fluid-filled cavity. The resultant evolutionary embryoblast-like entity has higher survivability and spatial cephalic-caudal growth organization with pluripotentiality that carry the correct DNA instructions to repair, and regenerate. The isolation and manipulation of these order structures can guide and control the regenerative pathway mechanism in human tumors as follows: modify and reprogram the phenotype of the tumor where these entities are generated, establish a reverse primordial microscopic mold to use the swirlonic collective behavior of cellular building blocks to regenerate injured tissues, convert cancer cells to a normal phenotype through regeneration using the organizational level and scale properties of reverse genetic guidance, global control of mitotic activity and morphogenetic movements avoiding their spread and metastasis, determining a better life prognosis for patients who incubate these entities in their tumors compared to those who do not express them. An emergent self-repair order structure, biological template to develop targeted therapeutic alternatives not only in cancer but also in treatment of autoimmune, viral diseases, and in regenerative medicine and rejuvenation.

Dent disease 1 (DD1) is a rare X-linked renal proximal tubulopathy characterized by low molecular weight proteinuria (LMWP) and variable degree of hypercalciuria, nephrocalcinosis and/or nephrolithiasis with progression to chronic kidney disease (CKD). Although loss-of-function mutations in the gene CLCN5 encoding the electrogenic Cl-/H+ antiporter ClC-5, which impair endocytic uptake in proximal tubule cells, cause the disease, there is poor genotype-phenotype correlation and their contribution to proximal tubule dysfunction remains unclear. Here, in order to discover the mechanisms leading to proximal tubule dysfunction due to ClC-5 loss-of-function, we have generated and characterized new human cellular models of DD1 by silencing CLCN5 and introducing the ClC-5 pathogenic mutants V523del, E527D and I524K into the human proximal tubule-derived cell line RPTEC/TERT1. Depletion of CLCN5 or expression of mutant ClC-5 impairs albumin endocytosis, increases substrate adhesion and decreases collective migration, which correlates with a less differentiated epithelial phenotype. Interestingly, although all conditions compromised the endocytic capacity in a similar way, their impact on gene expression profiles was different. Our DNA microarray studies show that ClC-5 silencing or mutant re-introduction alter pathways related to nephron development, anion homeostasis, organic acid transport, extracellular matrix organization and cell migration, compared to control cells. Cells carrying the V523del ClC-5 mutation show the largest differences in gene expression vs WT cells, which is in agreement with the more aggressive clinical phenotype observed in some DD1 patients. Overall, this work emphasizes the use of human proximal tubule derived cell models to identify the molecular processes underlying ClC-5 deficiency.

Rho-GTPase-activating proteins (Rho-GAPs) are essential upstream regulators of the Rho family of GTPases. Currently, it remains unclear if the phenotypic change caused by perturbations to a Rho-GAP is predictable from its structural sequence. Here we analyze the relationship between the morphological response of cells to the silencing of Rho-GAPs and their primary structure. For all possible pairs of 57 different Rho-GAPs expressed in MCF10A epithelial cells, the similarity in the Rho-GAP silencing-induced morphological change was quantified and compared to the similarity in the primary structure of the corresponding pairs. We found a distinct correlation between the morphological and structural similarities in a specific group of RhoA-targeting Rho-GAPs. Thus, the family-wide analysis revealed a common feature shared by the specific Rho-GAPs.

Inherited retinal degeneration (IRD) refers to untreatable blinding diseases characterized by progressive photoreceptor loss. Photoreceptor degeneration is often associated with an excessive activation of poly (ADP-ribose) polymerase (PARP) and Ca2+-dependent calpain-type proteases. To explore the interplay between PARP and calpain activity, we employed organotypic retinal explant cultures derived from wild-type mice and from the rd1 mouse model for IRD. Retinae were treated with the PARP inhibitors INO1001 or Olaparib, the poly (ADP-ribose) glycohydrolase (PARG) inhibitor JA2131, or the transient receptor potential channel M2 (TRPM2) blocker 8-Br-ADPR. Readouts included the TUNEL assay to detect cell death, in situ activity assays for histone-deacetylases (HDAC), PARP, and calpain, as well as immunostaining for activated calpain-2, and poly (ADP-ribose) (PAR). PARP, PARG, and TRPM2 inhibition reduced calpain activity and calpain-2 activation. PARP activity was decreased by PARP and TRPM2 inhibitors but not by PARG inhibition. Remarkably, the PARP inhibitor INO1001 increased HDAC activity unlike any of the other compounds. When combined with the PARG inhibitor JA2131, INO1001 reduced photoreceptor cell death in a synergistic fashion, although such synergy was not observed for calpain or PARP activity. Moreover, synergistic photoreceptor preservation was not observed when JA2131 was combined with the PARP inhibitor Olaparib. Overall, these results indicate that in rd1 photoreceptors, PARP controls calpain activity via PARG and TRPM2-induced Ca2+ influx. We also characterize INO1001 as potentially more beneficial for IRD treatment than Olaparib. Our study details the complexity of PARP-signalling in photoreceptors and identifies PARG and TRPM2 as new targets for IRD therapy development.

Nephronophthisis (NPH) is a heterogeneous, autosomal recessive ciliopathy and an important cause of end-stage renal disease (ESRD) in children and young adults. Since its classification as ciliopathy in 2003, NPH disease causal attribution had been focused primarily on ciliary dysfunction. The finding that ciliopathy players are involved in the DNA damage response (DDR) signaling resulted in a paradigm shift in thinking on NPH disease aetiology. Mutations in NPHP1 are the leading cause of NPH, but the underlying mechanisms that lead to the disease phenotype remain poorly understood. Here, nephrocystin-1 depleted kidney organoids were generated and characterized to address this knowledge gap. We used CRISPR/Cas9 to generate NPHP1 control (NPHP1WT) and two mutant (NPHP1ko1 and NPHP1ko2.) cell lines from healthy human induced pluripotent stem cells (iPSC), differentiated into kidney organoids in an air-liquid interface following an optimized protocol. Upon loss of nephrocystin-1, kidney organoids showed impaired nephron structures and loss of glomerular mesangial and distal tubular cells. Furthermore, NPHP1 depleted organoids exhibited a persistent inability to repair DNA lesions and showed increased senescence and fibrosis characteristics. Dynamic subcellular localization of nephrocystin-1 in NPHP1WT, particularly its translocation to nuclei 15 min post-UVC light exposure, suggested its direct involvement in the DDR. In conclusion, a novel NPHP1-depleted kidney organoid model was established, providing a platform to comprehensively study DNA damage, senescence and fibrosis simultaneously upon nephrocystin-1 loss. This advanced model aids in the understanding of the pathophysiology of NPH and paves the way towards identifying novel druggable targets.

Parkinsons Disease is the second most common neurodegenerative disorder worldwide, with growing numbers and considerable societal and economic concerns. Human cell culture systems are efficient models for neurodegenerative disorders and allow for personalized, non-invasive analysis of cellular and molecular disease mechanisms. Midbrain organoids and assembloids are advanced 3D culture systems that recapitulate the human midbrain, which is highly affected by Parkinsons disease. Here, we used healthy control and patient-specific midbrain assembloids to assess mitochondrial DNA phenotypes and NfL levels alongside neurodegeneration and alpha-synuclein phosphorylation. Importantly, alterations in mitochondrial DNA homeostasis and NfL levels can be assayed in the supernatant and therefore are particularly suitable as biomarkers and for high throughput screening approaches.

Stress granules are cytoplasmic inclusions1 with cyto-protective functions2-6 assembling in response to stress. They are now accepted to be part of the pathological mechanism in several diseases, from cancer to neurodegenerative disorders7-10. However, the field is still struggling to find common regulators of their assembly and function7,11. In this study, we describe an unraveled mechanism involving lipid raft, via gangliosides and cholesterol, in the regulation of SG formation. This is the first report about regulation of SG by the cell membrane composition. This discovery could have a significant impact on the understanding of several disease mechanism. MATERIAL AND METHODESO_ST_ABSCell culture & cell treatmentC_ST_ABSMDA-MB-231 (ATCC) and SH-SY5Y (ATCC) cells were maintained at 37 {degrees}C with 5% CO2 in Gibco Dulbeccos Modified Eagle Medium: Nutrient Mixture F12 (DMEM-F12, GIBCO, Waltham, MA, USA) supplemented with 10% Fetal Bovine Serum (FBS, Eurobio, Les Ulis, France), 20 mM HEPES (GIBCO, Waltham, MA, USA), 1X Penicillin streptomycin (GIBCO, Waltham, MA, USA). Cells are treated with methyl-{beta}-cyclodextrine (M{beta}CD) (MDA-MD-231 5mM, SH-SY5Y 1mM) 48h before experimentation, or with d,l-threo-l-Phenyl-2-hexadecanoylamino-3-morpholino-1-propanol (PPMP) (MDA-MD-231 5M, SH-SY5Y 10M) for 24h. ImmunofluorescenceCells were seeded on coverslips, treated 48h with PPMP or 24h with M{beta}CD before the experiment. After stress treatment, cells are washed quickly with PBS before to be fixed for 15min with 4% Paraformaldehyde (Thermo Scientific, Waltham, MA, USA) in PBS. Cells were then permeabilized and blocked with IF buffer PBS-0.3% TX100 (Euromedex, Souffelweyersheim, France), 1% Glycine (Sigma, Saint-Louis, MO, USA), 5% Normal Horse Serum (Sigma, Saint-Louis, MO, USA), 5% Bovine Serum Albumine (Sigma, Saint-Louis, MO, USA) for 30 min at room temperature. Primary antibodies (Table S1) were diluted in IF buffer and incubated 1 h at room temperature. Coverslips were washed three times for 5 min with 1X PBS between primary and secondary antibody incubations. Subsequently, secondary antibodies (Table S1) were added along with DAPI for 1 h at room temperature in IF buffer. Cells were washed extensively 3 times with 1X PBS and mounted with ProLong Antifade reagent (Invitrogen, Carlsbad, CA, USA). Pictures were taken with confocal microscope LEICA LSM880 Western BlotFollowing drug(s) treatment(s), cells were washed with phosphate-buffered saline (PBS) and lysed in RIPA buffer (150mM NaCl, 50mM Tris pH7.4, 1%TritonX100, 0.1% SDS, 1% Sodiun desoxycholate) with Halt phosphatase and protease inhibitors (Thermo Scientific). Laemmlis sample buffer supplemented was added to samples to 1X final concentration. Samples were boiled, 5min 95{degrees}C before being loaded on a NuPAGE 4-12% Bis-Tris gel (Invitrogen) and transferred to nitrocellulose membrane (GE Healthcare). Membranes were blocked with Tris-buffered saline with 0.1% Tween-20 (TBS-T) with 5% BSA for at least 30 min at room temperature. Antibodies were diluted in 2.5% BSA in TBS-T. Primary antibodies were incubated overnight at 4{degrees}C and secondary antibodies for 1 h at room temperature; mouse anti G3BP1 antibody (Santa Cruz sc-365338), rabbit anti Caprin-1 antibody (ProteinTech Group 15112-1-AP), mouse anti puromycin antibody (Millipore MABE342), mouse anti GAPDH (abcam ab8245). Antibody detection was performed using SuperSignal West Pico Chemiluminescent Substrate (Thermo Scientific). Revelation of the blot was made using G:BOX machine (Syngene) via the GeneSys software. Blot analysis and quantification were done using ImageJ software. Statistical AnalysisStatistical analyses were done on 3 independent experiments. Student T-TEST were performed to compare control to PPMP samples or control to M{beta}CD samples.

Promyelocytic leukemia-nuclear bodies (PML-NBs) are dot-like protein assemblies and implicated in the pathogenesis of leukemia and viral infection. PML is the scaffold protein of PML-NB and its client proteins such as SUMO, DAXX, and Sp100 reside in PML-NBs. It is known that a short exposure to trivalent arsenic (As3+) induces the solubility change and the subsequent SUMOylation of PML, and the SUMO interacting motif (SIM) is not necessary for these biochemical changes. However, it has not been well studied how As3+ initiates or enhances the association of SUMO with PML and the other PML-NB client proteins. Here, we report that As3+ enhanced non-covalent association of PML with SUMO via the SUMO-SIM interaction which is dispensable for the solubility change and SUMOylation of PML. We also report that the As3+-induced solubility change of PML was not affected by ML792, a SUMO E1 enzyme inhibitor, even though the nuclear localization of SUMO2/3 and protein SUMOylation were halted by ML792. As3+ did not change the solubility of DAXX and SUMOylation enzymes such as SAE1, UBA2, and UBC9. In contrast, As3+ induced SUMOylation of Sp100 with a concomitant loss of its solubility like PML in human leukemia cell lines. Our current results indicate that both covalent and non-covalent associations of SUMO with PML are increased in As3+-exposed cells, and Sp100 may play a role in the maintenance of PML-NBs.

Unrestrained transcriptional activity of {beta}-CATENIN and its binding partner TCF7L2 frequently underlies colorectal tumor initiation and is considered an obligatory oncogenic driver throughout intestinal carcinogenesis. Yet, the TCF7L2 gene carries inactivating mutations in about 10 % of colorectal tumors and is non-essential in colorectal cancer (CRC) cell lines. To determine whether CRC cells acquire TCF7L2-independence through cancer-specific compensation by other T-cell factor (TCF)/lymphoid enhancer-binding factor (LEF) family members, or rather lose addiction to {beta}-CATENIN/TCF7L2-driven gene expression altogether, we generated multiple CRC cell lines entirely negative for TCF/LEF or {beta}-CATENIN expression. Viability of these cells demonstrates complete {beta}-CATENIN- and TCF/LEF-independence, albeit one {beta}-CATENIN-deficient cell line eventually became senescent. Absence of TCF/LEF proteins and {beta}-CATENIN consistently impaired CRC cell proliferation, reminiscent of mitogenic effects of WNT/{beta}-CATENIN signaling in the healthy intestine. Despite this common phenotype, {beta}-CATENIN-deficient cells exhibited highly cell-line-specific gene expression changes with little overlap between {beta}-CATENIN- and TCF7L2-dependent transcriptomes. Apparently, {beta}-CATENIN and TCF7L2 control sizeable fractions of their target genes independently from each other. The observed divergence of {beta}-CATENIN and TCF7L2 transcriptional programs, and the finding that neither {beta}-CATENIN nor TCF/LEF activity is strictly required for CRC cell survival has important implications when evaluating these factors as potential drug targets.

Inherited retinal degenerative diseases such as Retinitis Pigmentosa (RP) result in progressive loss of photoreceptors until an individual is completely blind. A hallmark of these diseases is progressive structural and functional remodeling of the remaining retinal neurons as rod photoreceptors are lost. While many studies focus on regenerative or bionic therapies to restore vision, extensive remodeling of retinal cell types throughout the course of retinal degenerative diseases stands as a barrier for successful implementation of these strategies. As a window onto the molecular basis of remodeling, we have performed a comparative analysis of single-cell transcriptome data from adult Zebrafish retina of wild-type and a P23H mutant rhodopsin model of RP. In addition to providing a benchmark atlas of retinal cell type transcriptomes in the wild-type adult Zebrafish retina, we find transcriptional changes in essentially all retinal cell types in the P23H model. Increased oxidative stress is evident not only in the rods but also in cones, retinal pigmented epithelium (RPE) and to a lesser extent in amacrine and bipolar cells. Metabolic changes increasing oxidative metabolism and glycolysis are found in rods and cones, while evidence of increased activity of the mitochondrial electron transport chain is found in retinal ganglion cells (RGCs). Evidence of synaptic remodeling is found throughout the retina, with changes to increase synaptic transmission in photoreceptors and bipolar cells, increased ionotropic glutamate receptors in amacrine and ganglion cells, and dendritic and axon remodeling throughout. Surprisingly, RPE, cones and bipolar cells in the P23H retinas also have increased expression of genes involved in circadian rhythm regulation. While this model system undergoes continuous regeneration, ongoing remodeling impacts the entire retina. This comprehensive transcriptomic analysis provides a molecular road map to understand how the retina remodels in the context of chronic retinal degeneration with ongoing regeneration.

Traumatic brain injury (TBI) is among the main causes of sudden death after head trauma. These injuries can result in severe degeneration and neuronal cell death in the CNS, including the retina which is a crucial part of the brain responsible for perceiving and transmitting visual information. The long-term effects of mild-repetitive TBI (rmTBI) are far less studied thus far, even though damages induced by repetitive injuries occurring in the brain are more common, especially amongst athletes. rmTBI can also have a detrimental effect on the retina and the pathophysiology of these injuries are likely to differ from the severe TBI (sTBI) retinal injury. Here we showed how rmTBI and sTBI can dissimilarly affect the retina. Our results indicate an increase in the number of activated microglial cells and Caspase3-positive cells in the retina in both traumatic models, suggesting a rise in the level of inflammation and cell death after TBI. The pattern of microglial activation appears evenly distributed and widespread but differs amongst the various retinal layers. sTBI induced microgial activation in both the superficial and deep retinal layers. In contrast to sTBI, no significant change occurred following the repetitive mild injury in the superficial layer, only the deep layer (spanning from the inner nuclear layer to the outer plexiform layer) shows microglial activation. This difference suggests that alternate response mechanisms play a role in the case of the different TBI incidents. The Caspase3 activation pattern showed a uniform increase in both the superficial and deep layers of the retina. This suggests a different action in the course of the disease in sTBI and rmTBI models and points to the need for new diagnostic procedures. Our present results suggest that the retina might serve as such a model of head injuries since the retinal tissue reacts to both forms of TBI and is the most accessible part of the human brain.

Age-related macular degeneration (AMD) is a blinding disease characterised by dysfunction of the retinal pigmented epithelium (RPE) which culminates in disruption or loss of the neurosensory retina. Genome-wide association studies have identified >65 genetic risk factors for AMD, including the TMEM97 locus. TMEM97 encodes the Sigma-2 receptor which is involved in apoptosis and cytotoxicity across a range of neurodegenerative diseases. However, the expression pattern of TMEM97 in the human retina and its functional role in retinal cells has remained elusive. Here we utilised CRISPR interference (CRISPRi) to investigate the functional role of TMEM97 in the retina. Transcriptome analysis of all major cell types within the human retina showed that TMEM97 is expressed in the RPE, retinal ganglion cells (RGCs) and amacrine cells. Using CRISPRi, we performed loss-of-function study of TMEM97 in the human RPE cell line, ARPE19. We generated a stable ARPE19 cell line expressing dCas9-KRAB which facilitated knockdown of TMEM97 using specific sgRNAs. Our results show that knockdown of TMEM97 in ARPE19 exerts a protective effect against oxidative stress-induced cell death. This work provides the first functional study of TMEM97 in RPE and supports the role of TMEM97 in AMD pathobiology. Our study highlights the potential for using CRISPRi to study AMD genetics, and the CRISPRi cell line generated here provided an useful in vitro tool for functional studies of other AMD-associated genes.

Convincing evidence has documented that mechanical vibrations profoundly affect the behaviour of different cell types and even the functions of different organs. Pressure waves such as those of sound could affect cytoskeletal molecules with coherent changes in their spatial organization and are conveyed to cellular nucleus via mechanotransduction. HL1 cells were grown and exposed to different sounds. Subsequently, cells were stained for phalloidin, beta-actin, alpha-tubulin, alpha-actinin-1 and MitoTracker(R) mitochondrial probe. The cells were analyzed with time-lapse and immunofluorescence/confocal microscopy. In this paper, we describe that different sound stimuli seem to influence the growth or death of HL1 cells, resulting in a different mitochondrial localization and expression of cytoskeletal proteins. Since the cellular behaviour seems to correlate with the meaning of the sound used, we speculate that it can be "understood" by the cells by virtue of the different sound waves geometric properties that we have photographed and filmed. A theoretical physical model is proposed to explain our preliminary results.

Wolman disease (WD) is a severe lysosomal storage disorder characterized by fatal lipid accumulation caused by the deficiency of a lipid metabolic enzyme, Lysosomal Acid Lipase (LAL), involved in the lysosomal hydrolysis of cholesterols and triglycerides. Due to the imbalance of lipids homeostasis, WD patients suffer from severe hepatosplenomegaly, hepatic failure and adrenal calcification resulting in a premature infant death within the first year of age. In this work, we explored multiple imaging analyses to fully characterize the phenotype of LAL deficient cells. In particular, we stained WD patients fibroblasts for intracellular lipid droplets (LD) and lysosomes and we analysed staining intensity and granularity as well as an increased number of LD and lysosomes using fluorescence wide field microscopy, confocal microscopy, conventional and image flow cytometry. Noteworthy, we showed that lipid homeostasis was restored upon delivery of a functional LAL transgene. Finally, since fibroblasts cannot be used as routine clinical test as they are difficult to collect from WD patients, we confirmed our observations in LAL deficient human blood cell lines and in peripheral blood mononuclear cells (PBMC) from LAL deficient (LAL-D) mouse model, as a proxy for easily accessible WD PBMC. Overall, we expect that this novel imaging analysis pipeline will help to diagnose WD, follow its progression and evaluate the success of enzyme replacement therapy or gene correction strategies for WD as well as other lysosomal storage disorders.

Axon degeneration (AxD), accompanied by glial remodeling, is a pathological hallmark of many neurodegenerative diseases, leading to the disruption of neuronal connectivity [1-3]. Understanding the mechanisms in neurons and glia that regulate AxD is essential for developing therapeutic strategies to prevent or mitigate axon loss. Wallerian degeneration (WD) is a well-established model to study the mechanisms of nerve injury-induced AxD, glial responses, and axon-glia interactions. We recently showed that Schwann cells (SCs), the axon-associated glia of the peripheral nervous system, exert protective effects on axons through their rapid metabolic injury response [4]. Enhancing this SC response promotes axon protection during WD [4]. A prior study reported that eliminating the orphan tumor necrosis factor receptor DR6 (death receptor 6, Tnfrsf21) strongly delays AxD and alters SC injury responses during WD [5], suggesting a possible intersection with our findings. Here, we rigorously revisit the role of DR6 in WD using two independent DR6 knockout mouse lines including the same model used in the previous study. Surprisingly, in striking contrast to the earlier report, we observed no impact of DR6 deletion on AxD kinetics or SC injury responses across a range of WD assays. Moreover, injured axons in primary neuronal cultures lacking DR6 degenerated at a similar rate as wild-type axons. We conclude that DR6 is dispensable for the regulation of AxD and glial nerve injury responses during WD. Our data argue that any therapeutic benefit from DR6 suppression in neurodegeneration models occurs through mechanisms independent of WD.

More than 700 pathogenic or probably pathogenic variations have been identified in the RYR1 gene causing various myopathies collectively known as "RYR1-related myopathies". Currently, there is no treatment for these myopathies, and gene therapy stands out as one of the most promising approaches. In the context of a dominant form of Central Core Disease due to a RYR1 mutation, we aimed at showing the functional benefit of inactivating specifically the mutated RYR1 allele by guiding CRISPR/Cas9 cleavages onto frequent single nucleotide polymorphisms (SNPs) segregating on the same chromosome. Whole-genome sequencing was used to pinpoint SNPs localized on the mutant RYR1 allele and identified specific CRISPR/Cas9 guide-RNAs. Lentiviruses encoding these guide-RNAs and the SpCas9 nuclease were used to transduce immortalized patient muscle cells, inducing the specific deletion of the mutant RYR1 allele. The efficiency of the deletion was assessed at both DNA and RNA levels and at the functional level after monitoring calcium release induced by the stimulation of the RyR1-channel. This study provides in-cellulo proof of concept regarding the benefits of mutant RYR1 allele deletion, in the case of a dominant RYR1 mutation, from both a molecular and functional perspective. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/576997v1_ufig1.gif" ALT="Figure 1"> View larger version (60K): org.highwire.dtl.DTLVardef@484a3borg.highwire.dtl.DTLVardef@1a842org.highwire.dtl.DTLVardef@cda3d5org.highwire.dtl.DTLVardef@befd91_HPS_FORMAT_FIGEXP M_FIG C_FIG eTOC synopsisMutations in the RYR1 gene, encoding a calcium channel required for muscle contraction, cause severe myopathies. In this study, Marty and colleagues demonstrate the functional benefit of suppression of a mutant RYR1 allele using CRISPR/Cas9, in the case of a dominant mutation, leaving the wild type allele alone.

Spinocerebellar Ataxia type 1 (SCA1) is an autosomal dominant neurodegenerative disorder caused by a gain-of-function protein with toxic activities, containing an expanded polyQ tract in the coding region. Actually, there are no treatments available to delay the onset, stop or slow down the progression of this pathology. Many approaches developed over the years involve the use of siRNAs and antisense oligonucleotides (ASOs). Here we develop and validate a CRISPR/Cas9 therapeutic strategy in fibroblasts isolated from SCA1 patients. We started from the screening of 10 different sgRNAs able to recognize regions upstream and downstream the CAG repeats, in exon 8 of ATXN1 gene. The two most promising sgRNAs, G3 and G8, whose efficiency was evaluated with an in vitro system, significantly downregulated the ATXN 1 protein expression. This downregulation was due to the introduction of indels mutations into the ATXN1 gene. Notably, with an RNA-seq analysis, we demonstrated minimal off-target effects of our sgRNAs. These preliminary results support CRISPR/Cas9 as a promising approach for treated polyQ-expanded diseases.