Activation of naïve CD4+ T cells re-tunes STAT1 signaling to deliver unique cytokine responses in memory CD4+ T cells.

The cytokine IL-6 controls the survival, proliferation and effector characteristics of lymphocytes through activation of the transcription factors STAT1 and STAT3. While STAT3 activity is an ever-present feature of IL-6 signaling in CD4+ T cells, prior activation via the T cell antigen receptor limits IL-6's control of STAT1 in effector and memory populations. Here we found that phosphorylation of STAT1 in response to IL-6 was regulated by the tyrosine phosphatases PTPN2 and PTPN22 expressed in response to the activation of naïve CD4+ T cells. Transcriptomics and chromatin immunoprecipitation-sequencing (ChIP-seq) of IL-6 responses in naïve and effector memory CD4+ T cells showed how the suppression of STAT1 activation shaped the functional identity and effector characteristics of memory CD4+ T cells. Thus, tyrosine phosphatases induced by the activation of naïve T cells determine the way activated or memory CD4+ T cells sense and interpret cytokine signals.

Corrigendum: IL-6 as a keystone cytokine in health and disease.

This corrects the article DOI: 10.1038/ni.3153.

Trial of N-Acetyl-l-Leucine in Niemann-Pick Disease Type C.

BACKGROUND: Niemann-Pick disease type C is a rare lysosomal storage disorder. We evaluated the safety and efficacy of N-acetyl-l-leucine (NALL), an agent that potentially ameliorates lysosomal and metabolic dysfunction, for the treatment of Niemann-Pick disease type C. METHODS: In this double-blind, placebo-controlled, crossover trial, we randomly assigned patients 4 years of age or older with genetically confirmed Niemann-Pick disease type C in a 1:1 ratio to receive NALL for 12 weeks, followed by placebo for 12 weeks, or to receive placebo for 12 weeks, followed by NALL for 12 weeks. NALL or matching placebo was administered orally two to three times per day, with patients 4 to 12 years of age receiving weight-based doses (2 to 4 g per day) and those 13 years of age or older receiving a dose of 4 g per day. The primary end point was the total score on the Scale for the Assessment and Rating of Ataxia (SARA; range, 0 to 40, with lower scores indicating better neurologic status). Secondary end points included scores on the Clinical Global Impression of Improvement, the Spinocerebellar Ataxia Functional Index, and the Modified Disability Rating Scale. Crossover data from the two 12-week periods in each group were included in the comparisons of NALL with placebo. RESULTS: A total of 60 patients 5 to 67 years of age were enrolled. The mean baseline SARA total scores used in the primary analysis were 15.88 before receipt of the first dose of NALL (60 patients) and 15.68 before receipt of the first dose of placebo (59 patients; 1 patient never received placebo). The mean (±SD) change from baseline in the SARA total score was -1.97±2.43 points after 12 weeks of receiving NALL and -0.60±2.39 points after 12 weeks of receiving placebo (least-squares mean difference, -1.28 points; 95% confidence interval, -1.91 to -0.65; P<0.001). The results for the secondary end points were generally supportive of the findings in the primary analysis, but these were not adjusted for multiple comparisons. The incidence of adverse events was similar with NALL and placebo, and no treatment-related serious adverse events occurred. CONCLUSIONS: Among patients with Niemann-Pick disease type C, treatment with NALL for 12 weeks led to better neurologic status than placebo. A longer period is needed to determine the long-term effects of this agent in patients with Niemann-Pick disease type C. (Funded by IntraBio; ClinicalTrials.gov number, NCT05163288; EudraCT number, 2021-005356-10.).

IL-6 as a keystone cytokine in health and disease.

Interleukin 6 (IL-6) has a broad effect on cells of the immune system and those not of the immune system and often displays hormone-like characteristics that affect homeostatic processes. IL-6 has context-dependent pro- and anti-inflammatory properties and is now regarded as a prominent target for clinical intervention. However, the signaling cassette that controls the activity of IL-6 is complicated, and distinct intervention strategies can inhibit this pathway. Clinical experience with antagonists of IL-6 has raised new questions about how and when to block this cytokine to improve disease outcome and patient wellbeing. Here we discuss the effect of IL-6 on innate and adaptive immunity and the possible advantages of various antagonists of IL-6 and consider how the immunobiology of IL-6 may inform clinical decisions.

On-going Mechanical Damage from Mastication Drives Homeostatic Th17 Cell Responses at the Oral Barrier.

Immuno-surveillance networks operating at barrier sites are tuned by local tissue cues to ensure effective immunity. Site-specific commensal bacteria provide key signals ensuring host defense in the skin and gut. However, how the oral microbiome and tissue-specific signals balance immunity and regulation at the gingiva, a key oral barrier, remains minimally explored. In contrast to the skin and gut, we demonstrate that gingiva-resident T helper 17 (Th17) cells developed via a commensal colonization-independent mechanism. Accumulation of Th17 cells at the gingiva was driven in response to the physiological barrier damage that occurs during mastication. Physiological mechanical damage, via induction of interleukin 6 (IL-6) from epithelial cells, tailored effector T cell function, promoting increases in gingival Th17 cell numbers. These data highlight that diverse tissue-specific mechanisms govern education of Th17 cell responses and demonstrate that mechanical damage helps define the immune tone of this important oral barrier.

Th1 Cells Alter the Inflammatory Signature of IL-6 by Channeling STAT Transcription Factors to Alu-like Retroelements.

Cytokines that signal via STAT1 and STAT3 transcription factors instruct decisions affecting tissue homeostasis, antimicrobial host defense, and inflammation-induced tissue injury. To understand the coordination of these activities, we applied RNA sequencing, chromatin immunoprecipitation sequencing, and assay for transposase-accessible chromatin with high-throughput sequencing to identify the transcriptional output of STAT1 and STAT3 in peritoneal tissues from mice during acute resolving inflammation and inflammation primed to drive fibrosis. Bioinformatics focused on the transcriptional signature of the immunomodulatory cytokine IL-6 in both settings and examined how profibrotic IFN-γ-secreting CD4+ T cells altered the interpretation of STAT1 and STAT3 cytokine cues. In resolving inflammation, STAT1 and STAT3 cooperated to drive stromal gene expression affecting antimicrobial immunity and tissue homeostasis. The introduction of IFN-γ-secreting CD4+ T cells altered this transcriptional program and channeled STAT1 and STAT3 to a previously latent IFN-γ activation site motif in Alu-like elements. STAT1 and STAT3 binding to this conserved sequence revealed evidence of reciprocal cross-regulation and gene signatures relevant to pathophysiology. Thus, we propose that effector T cells retune the transcriptional output of IL-6 by shaping a regulatory interplay between STAT1 and STAT3 in inflammation.

A large animal model of RDH5-associated retinopathy recapitulates important features of the human phenotype.

Pathogenic variants in retinol dehydrogenase 5 (RDH5) attenuate supply of 11-cis-retinal to photoreceptors leading to a range of clinical phenotypes including night blindness because of markedly slowed rod dark adaptation and in some patients, macular atrophy. Current animal models (such as Rdh5-/- mice) fail to recapitulate the functional or degenerative phenotype. Addressing this need for a relevant animal model we present a new domestic cat model with a loss-of-function missense mutation in RDH5 (c.542G > T; p.Gly181Val). As with patients, affected cats have a marked delay in recovery of dark adaptation. In addition, the cats develop a degeneration of the area centralis (equivalent to the human macula). This recapitulates the development of macular atrophy that is reported in a subset of patients with RDH5 mutations and is shown in this paper in seven patients with biallelic RDH5 mutations. There is notable variability in the age at onset of the area centralis changes in the cat, with most developing changes as juveniles but some not showing changes over the first few years of age. There is similar variability in development of macular atrophy in patients and while age is a risk factor, it is hypothesized that genetic modifying loci influence disease severity, and we suspect the same is true in the cat model. This novel cat model provides opportunities to improve molecular understanding of macular atrophy and test therapeutic interventions for RDH5-associated retinopathies.

Hematopoietic Stem- and Progenitor-Cell Gene Therapy for Hurler Syndrome.

BACKGROUND: Allogeneic hematopoietic stem-cell transplantation is the standard of care for Hurler syndrome (mucopolysaccharidosis type I, Hurler variant [MPSIH]). However, this treatment is only partially curative and is associated with complications. METHODS: We are conducting an ongoing study involving eight children with MPSIH. At enrollment, the children lacked a suitable allogeneic donor and had a Developmental Quotient or Intelligence Quotient score above 70 (i.e., none had moderate or severe cognitive impairment). The children received autologous hematopoietic stem and progenitor cells (HSPCs) transduced ex vivo with an α-L-iduronidase (IDUA)-encoding lentiviral vector after myeloablative conditioning. Safety and correction of blood IDUA activity up to supraphysiologic levels were the primary end points. Clearance of lysosomal storage material as well as skeletal and neurophysiological development were assessed as secondary and exploratory end points. The planned duration of the study is 5 years. RESULTS: We now report interim results. The children's mean (±SD) age at the time of HSPC gene therapy was 1.9±0.5 years. At a median follow-up of 2.10 years, the procedure had a safety profile similar to that known for autologous hematopoietic stem-cell transplantation. All the patients showed prompt and sustained engraftment of gene-corrected cells and had supraphysiologic blood IDUA activity within a month, which was maintained up to the latest follow-up. Urinary glycosaminoglycan (GAG) excretion decreased steeply, reaching normal levels at 12 months in four of five patients who could be evaluated. Previously undetectable levels of IDUA activity in the cerebrospinal fluid became detectable after gene therapy and were associated with local clearance of GAGs. Patients showed stable cognitive performance, stable motor skills corresponding to continued motor development, improved or stable findings on magnetic resonance imaging of the brain and spine, reduced joint stiffness, and normal growth in line with World Health Organization growth charts. CONCLUSIONS: The delivery of HSPC gene therapy in patients with MPSIH resulted in extensive metabolic correction in peripheral tissues and the central nervous system. (Funded by Fondazione Telethon and others; ClinicalTrials.gov number, NCT03488394; EudraCT number, 2017-002430-23.).

Cross-species transcriptomics identifies obesity associated genes between human and mouse studies.

BACKGROUND: Fundamentally defined by an imbalance in energy consumption and energy expenditure, obesity is a significant risk factor of several musculoskeletal conditions including osteoarthritis (OA). High-fat diets and sedentary lifestyle leads to increased adiposity resulting in systemic inflammation due to the endocrine properties of adipose tissue producing inflammatory cytokines and adipokines. We previously showed serum levels of specific adipokines are associated with biomarkers of bone remodelling and cartilage volume loss in knee OA patients. Whilst more recently we find the metabolic consequence of obesity drives the enrichment of pro-inflammatory fibroblast subsets within joint synovial tissues in obese individuals compared to those of BMI defined 'health weight'. As such this present study identifies obesity-associated genes in OA joint tissues which are conserved across species and conditions. METHODS: The study utilised 6 publicly available bulk and single-cell transcriptomic datasets from human and mice studies downloaded from Gene Expression Omnibus (GEO). Machine learning models were employed to model and statistically test datasets for conserved gene expression profiles. Identified genes were validated in OA tissues from obese and healthy weight individuals using quantitative PCR method (N = 38). Obese and healthy-weight patients were categorised by BMI > 30 and BMI between 18 and 24.9 respectively. Informed consent was obtained from all study participants who were scheduled to undergo elective arthroplasty. RESULTS: Principal component analysis (PCA) was used to investigate the variations between classes of mouse and human data which confirmed variation between obese and healthy populations. Differential gene expression analysis filtered on adjusted p-values of p < 0.05, identified differentially expressed genes (DEGs) in mouse and human datasets. DEGs were analysed further using area under curve (AUC) which identified 12 genes. Pathway enrichment analysis suggests these genes were involved in the biosynthesis and elongation of fatty acids and the transport, oxidation, and catabolic processing of lipids. qPCR validation found the majority of genes showed a tendency to be upregulated in joint tissues from obese participants. Three validated genes, IGFBP2 (p = 0.0363), DOK6 (0.0451) and CASP1 (0.0412) were found to be significantly different in obese joint tissues compared to lean-weight joint tissues. CONCLUSIONS: The present study has employed machine learning models across several published obesity datasets to identify obesity-associated genes which are validated in joint tissues from OA. These results suggest obesity-associated genes are conserved across conditions and may be fundamental in accelerating disease in obese individuals. Whilst further validations and additional conditions remain to be tested in this model, identifying obesity-associated genes in this way may serve as a global aid for patient stratification giving rise to the potential of targeted therapeutic interventions in such patient subpopulations.

Improving newborn screening test performance for metachromatic leukodystrophy: Recommendation from a pre-pilot study that identified a late-infantile case for treatment.

Metachromatic leukodystrophy (MLD) is a devastating rare neurodegenerative disease. Typically, loss of motor and cognitive skills precedes early death. The disease is characterised by deficient lysosomal arylsulphatase A (ARSA) activity and an accumulation of undegraded sulphatide due to pathogenic variants in the ARSA gene. Atidarsagene autotemcel (arsa-cel), an ex vivo haematopoietic stem cell gene therapy was approved for use in the UK in 2021 to treat early-onset forms of pre- or early-symptomatic MLD. Optimal outcomes require early diagnosis, but in the absence of family history this is difficult to achieve without newborn screening (NBS). A pre-pilot MLD NBS study was conducted as a feasibility study in Manchester UK using a two-tiered screening test algorithm. Pre-established cutoff values (COV) for the first-tier C16:0 sulphatide (C16:0-S) and the second-tier ARSA tests were evaluated. Before the pre-pilot study, initial test validation using non­neonatal diagnostic bloodspots demonstrated ARSA pseudodeficiency status was associated with normal C16:0-S results for age (n = 43) and hence not expected to cause false positive results in this first-tier test. Instability of ARSA in bloodspot required transfer of NBS bloodspots from ambient temperature to -20°C storage within 7-8 days after heel prick, the earliest possible in this UK pre-pilot study. Eleven of 3687 de-identified NBS samples in the pre-pilot were positive for C16:0-S based on the pre-established COV of ≥170 nmol/l or ≥ 1.8 multiples of median (MoM). All 11 samples were subsequently tested negative determined by the ARSA COV of <20% mean of negative controls. However, two of 20 NBS samples from MLD patients would be missed by this C16:0-S COV. A further suspected false negative case that displayed 4% mean ARSA activity by single ARSA analysis for the initial test validation was confirmed by genotyping of this NBS bloodspot, a severe late infantile MLD phenotype was predicted. This led to urgent assessment of this child by authority approval and timely commencement of arsa-cel gene therapy at 11 months old. Secondary C16:0-S analysis of this NBS bloodspot was 150 nmol/l or 1.67 MoM. This was the lowest result reported thus far, a new COV of 1.65 MoM is recommended for future pilot studies. Furthermore, preliminary data of this study showed C16:1-OH sulphatide is more specific for MLD than C16:0-S. In conclusion, this pre-pilot study adds to the international evidence that recommends newborn screening for MLD, making it possible for patients to benefit fully from treatment through early diagnosis.

Land surface conductance linked to precipitation: Co-evolution of vegetation and climate in Earth system models.

Vegetation and precipitation are known to fundamentally influence each other. However, this interdependence is not fully represented in climate models because the characteristics of land surface (canopy) conductance to water vapor and CO2 are determined independently of precipitation. Working within a coupled atmosphere and land modelling framework (CAM6/CLM5; coupled Community Atmosphere Model v6/Community Land Model v5), we have developed a new theoretical approach to characterizing land surface conductance by explicitly linking its dynamic properties to local precipitation, a robust proxy for moisture available to vegetation. This will enable regional surface conductance characteristics to shift fluidly with climate change in simulations, consistent with general principles of co-evolution of vegetation and climate. Testing within the CAM6/CLM5 framework shows that climate simulations incorporating the new theory outperform current default configurations across several error metrics for core output variables when measured against observational data. In climate simulations for the end of this century the new, adaptive stomatal conductance scheme provides a revised prognosis for average and extreme temperatures over several large regions, with increased primary productivity through central and east Asia, and higher rainfall through North Africa and the Middle East. The new projections also reveal more frequent heatwaves than originally estimated for the south-eastern US and sub-Saharan Africa but less frequent heatwaves across east Europe and northeast Asia. These developments have implications for evaluating food security and risks from extreme temperatures in areas that are vulnerable to climate change.

Risk factors for infection and outcomes in infants with neonatal encephalopathy: a cohort study.

BACKGROUND: To determine the association between early infection risk factors and short-term outcomes in infants with neonatal encephalopathy following perinatal asphyxia (NE). METHODS: A retrospective population-based cohort study utilizing the National Neonatal Research Database that included infants with NE admitted to neonatal units in England and Wales, Jan 2008-Feb 2018. EXPOSURE: one or more of rupture of membranes >18 h, maternal group B streptococcus colonization, chorioamnionitis, maternal pyrexia or antepartum antibiotics. PRIMARY OUTCOME: death or nasogastric feeds/nil by mouth (NG/NBM) at discharge. SECONDARY OUTCOMES: organ dysfunction; length of stay; intraventricular hemorrhage; antiseizure medications use. RESULTS: 998 (13.7%) out of 7265 NE infants had exposure to early infection risk factors. Primary outcome (20.3% vs. 23.1%, OR 0.87 (95% CI 0.71-1.08), p = 0.22), death (12.8% vs. 14.0%, p = 0.32) and NG/NBM (17.4% vs. 19.9%. p = 0.07) did not differ between the exposed and unexposed group. Time to full sucking feeds (OR 0.81 (0.69-0.95)), duration (OR 0.82 (0.71-0.95)) and the number of antiseizure medications (OR 0.84 (0.72-0.98)) were lower in exposed than unexposed infants after adjusting for confounders. Therapeutic hypothermia did not alter the results. CONCLUSIONS: Infants with NE exposed to risk factors for early-onset infection did not have worse short-term adverse outcomes. IMPACT: Risk factors for early-onset neonatal infection, including rupture of membranes >18 h, maternal group B streptococcus colonization, chorioamnionitis, maternal pyrexia or antepartum antibiotics, were not associated with death or short-term morbidity after cooling for NE. Despite exposure to risk factors for early-onset neonatal infection, infants with NE reached oral feeds earlier and needed fewer anti-seizure medications for a shorter duration than infants with NE but without such risk factors. This study supports current provision of therapeutic hypothermia for infants with NE and any risk factors for early-onset neonatal infection.

Long-term benefit of sotorasib in patients with KRAS G12C-mutated non-small-cell lung cancer: plain language summary.

WHAT IS THIS SUMMARY ABOUT?: This is a plain language summary of a study called CodeBreaK 100. The CodeBreaK 100 study included patients with non-small-cell lung cancer that had spread outside the lung (advanced). Lung cancer is one of the most common forms of cancer. CodeBreaK 100 specifically looked at patients with a particular change(mutation) in the KRAS gene resulting in the mutated protein called KRAS G12C. The KRAS G12C mutation can lead to development and growth of lung cancer. Patients received a treatment called sotorasib, which has accelerated approval or full approval in over 50 countries for patients with non-small-cell lung cancer with the KRAS G12C mutation. The CodeBreaK 100 study looked at whether sotorasib is a safe and effective treatment for advanced non-small-cell lung cancer. Sotorasib is designed to specifically target and lock the mutated KRAS protein in the inactive state to treat non-small-cell lung cancer. WHAT WERE THE RESULTS?: In total, 174 adults were treated with sotorasib. Treatment-related side effects were seen in 70% of patients and were severe in 21% of patients. The most common side effects included diarrhea, increased liver enzymes, nausea and tiredness. 70 (41%) patients responded to sotorasib and 144 (84%) patients had tumors that either remained stable or shrunk in size. 29 (41%) patients who responded to sotorasib responded for over 12 months. After 2 years, 9 patients with a response remained on sotorasib; there were no notable increases in tumor size or development of new tumors over this time. There were 5patients who received sotorasib for more than 2 years and continued to respond. Long-term benefit was seen for some patients. Patients also benefitted from treatment when the tumor expressed different amounts of a protein called PD-L1.In total, 33% of patients were still alive after 2 years. WHAT DO THE RESULTS MEAN?: Results show the long-term benefit of sotorasib therapy for people with advanced KRAS G12C-mutated non-small-cell lung cancer. Clinical Trial Registration: NCT03600883 (CodeBreaK 100) (ClinicalTrials.gov).

Development of a translatable gene augmentation therapy for CNGB1-retinitis pigmentosa.

In this study, we investigate a gene augmentation therapy candidate for the treatment of retinitis pigmentosa (RP) due to cyclic nucleotide-gated channel beta 1 (CNGB1) mutations. We use an adeno-associated virus serotype 5 with transgene under control of a novel short human rhodopsin promoter. The promoter/capsid combination drives efficient expression of a reporter gene (AAV5-RHO-eGFP) exclusively in rod photoreceptors in primate, dog, and mouse following subretinal delivery. The therapeutic vector (AAV5-RHO-CNGB1) delivered to the subretinal space of CNGB1 mutant dogs restores rod-mediated retinal function (electroretinographic responses and vision) for at least 12 months post treatment. Immunohistochemistry shows human CNGB1 is expressed in rod photoreceptors in the treated regions as well as restoration of expression and trafficking of the endogenous alpha subunit of the rod CNG channel required for normal channel formation. The treatment reverses abnormal accumulation of the second messenger, cyclic guanosine monophosphate, which occurs in rod photoreceptors of CNGB1 mutant dogs, confirming formation of a functional CNG channel. In vivo imaging shows long-term preservation of retinal structure. In conclusion, this study establishes the long-term efficacy of subretinal delivery of AAV5-RHO-CNGB1 to rescue the disease phenotype in a canine model of CNGB1-RP, confirming its suitability for future clinical development.

Development of the intelligent knee osteoarthritis lifestyle app: a person-based approach.

BACKGROUND: Knee osteoarthritis is one of the most prevalent long term health conditions globally. Exercise and physical activity are now widely recognised to significantly reduce joint pain, improve physical function and quality of life in patients with knee osteoarthritis. However, prescribed exercise without regular contact with a healthcare professional often results in lower adherence and poorer health outcomes. Digital mobile health (mHealth) technologies offer great potential to support people with long-term conditions such as knee osteoarthritis more efficiently and effectively and with relatively lower cost than existing interventions. However, there are currently very few mHealth interventions for the self-management of knee osteoarthritis. The aim of the present study was to describe the development process of a mHealth app to extend the support for physical activity and musculoskeletal health beyond short-term, structured rehabilitation through self-management, personalised physical activity, education, and social support. METHODS: The development of the intelligent knee osteoarthritis lifestyle application intervention involved an iterative and interconnected process comprising intervention 'planning' and 'optimisation' informed by the person-based approach framework for the development of digital health interventions. The planning phase involved a literature review and collection of qualitative data obtained from focus groups with individuals with knee osteoarthritis (n = 26) and interviews with relevant physiotherapists (n = 5) to generate 'guiding principles' for the intervention. The optimisation phase involved usability testing (n = 7) and qualitative 'think aloud' sessions (n = 6) with potential beneficiaries to refine the development of the intervention. RESULTS: Key themes that emerged from the qualitative data included the need for educational material, modifying activities to suit individual abilities and preferences as well as the inclusion of key features such as rehabilitation exercises. Following a user-trial further changes were made to improve the usability of the application. CONCLUSIONS: Using a systematic person-based, development approach, we have developed the intelligent knee osteoarthritis lifestyle application to help people maintain physical activity behaviour. The app extends the support for physical activity and musculoskeletal health beyond short-term, structured rehabilitation through personalised physical activity guidance, education, and social support.

Techniques for subretinal injections in animals.

Subretinal injections are not commonly performed during clinical treatment of animals but are frequently used in laboratory animal models to assess therapeutic efficacy and safety of gene and cell therapy products. Veterinary ophthalmologists are often employed to perform the injections in the laboratory animal setting, due to knowledge of comparative ocular anatomy between species and familiarity with operating on non-human eyes. Understanding the different approaches used for subretinal injection in each species and potential complications that may be encountered is vital to achieving successful and reproducible results. This manuscript provides a summary of different approaches to subretinal injections in the most common animal model species, along with information from published literature and experience of the authors to educate novice or experienced surgeons tasked with performing these injections for the first time.

Consensus guidelines for nomenclature of companion animal inherited retinal disorders.

Companion animals, namely dogs, cats, and horses, can be affected with many forms of hereditary retinal disease. The number of such diseases characterized in the last decade has increased substantially, and nomenclature is nonstandardized, heterogenous, and confusing. We provide in this viewpoint article consensus guidelines for naming of companion animal hereditary retinal diseases, either prospectively or retrospectively. These consensus guidelines have been developed with the purpose of standardizing nomenclature. We provide examples for the iterative nomenclature process and a comprehensive File S1 on proposed renaming of previously described diseases.

The Species Effect: Differential Sphingosine-1-Phosphate Responses in the Bone in Human Versus Mouse.

The deterioration of osteoblast-led bone formation and the upregulation of osteoclast-regulated bone resorption are the primary causes of bone diseases, including osteoporosis. Numerous circulating factors play a role in bone homeostasis by regulating osteoblast and osteoclast activity, including the sphingolipid-sphingosine-1-phosphate (S1P). However, to date no comprehensive studies have investigated the impact of S1P activity on human and murine osteoblasts and osteoclasts. We observed species-specific responses to S1P in both osteoblasts and osteoclasts, where S1P stimulated human osteoblast mineralisation and reduced human pre-osteoclast differentiation and mineral resorption, thereby favouring bone formation. The opposite was true for murine osteoblasts and osteoclasts, resulting in more mineral resorption and less mineral deposition. Species-specific differences in osteoblast responses to S1P were potentially explained by differential expression of S1P receptor 1. By contrast, human and murine osteoclasts expressed comparable levels of S1P receptors but showed differential expression patterns of the two sphingosine kinase enzymes responsible for S1P production. Ultimately, we reveal that murine models may not accurately represent how human bone cells will respond to S1P, and thus are not a suitable model for exploring S1P physiology or potential therapeutic agents.

Mutations in the Kinesin-2 Motor KIF3B Cause an Autosomal-Dominant Ciliopathy.

Kinesin-2 enables ciliary assembly and maintenance as an anterograde intraflagellar transport (IFT) motor. Molecular motor activity is driven by a heterotrimeric complex comprised of KIF3A and KIF3B or KIF3C plus one non-motor subunit, KIFAP3. Using exome sequencing, we identified heterozygous KIF3B variants in two unrelated families with hallmark ciliopathy phenotypes. In the first family, the proband presents with hepatic fibrosis, retinitis pigmentosa, and postaxial polydactyly; he harbors a de novo c.748G>C (p.Glu250Gln) variant affecting the kinesin motor domain encoded by KIF3B. The second family is a six-generation pedigree affected predominantly by retinitis pigmentosa. Affected individuals carry a heterozygous c.1568T>C (p.Leu523Pro) KIF3B variant segregating in an autosomal-dominant pattern. We observed a significant increase in primary cilia length in vitro in the context of either of the two mutations while variant KIF3B proteins retained stability indistinguishable from wild type. Furthermore, we tested the effects of KIF3B mutant mRNA expression in the developing zebrafish retina. In the presence of either missense variant, rhodopsin was sequestered to the photoreceptor rod inner segment layer with a concomitant increase in photoreceptor cilia length. Notably, impaired rhodopsin trafficking is also characteristic of recessive KIF3B models as exemplified by an early-onset, autosomal-recessive, progressive retinal degeneration in Bengal cats; we identified a c.1000G>A (p.Ala334Thr) KIF3B variant by genome-wide association study and whole-genome sequencing. Together, our genetic, cell-based, and in vivo modeling data delineate an autosomal-dominant syndromic retinal ciliopathy in humans and suggest that multiple KIF3B pathomechanisms can impair kinesin-driven ciliary transport in the photoreceptor.

Intraparenchymal convection enhanced delivery of AAV in sheep to treat Mucopolysaccharidosis IIIC.

BACKGROUND: Mucopolysaccharidosis IIIC (MPSIIIC) is one of four Sanfilippo diseases sharing clinical symptoms of severe cognitive decline and shortened lifespan. The missing enzyme, heparan sulfate acetyl-CoA: α-glucosaminide-N-acetyltransferase (HGSNAT), is bound to the lysosomal membrane, therefore cannot cross the blood-brain barrier or diffuse between cells. We previously demonstrated disease correction in MPSIIIC mice using an Adeno-Associated Vector (AAV) delivering HGSNAT via intraparenchymal brain injections using an AAV2 derived AAV-truetype (AAV-TT) serotype with improved distribution over AAV9. METHODS: Here, intraparenchymal AAV was delivered in sheep using catheters or Hamilton syringes, placed using Brainlab cranial navigation for convection enhanced delivery, to reduce proximal vector expression and improve spread. RESULTS: Hamilton syringes gave improved AAV-GFP distribution, despite lower vector doses and titres. AAV-TT-GFP displayed moderately better transduction compared to AAV9-GFP but both serotypes almost exclusively transduced neurons. Functional HGSNAT enzyme was detected in 24-37% of a 140g gyrencephalic sheep brain using AAV9-HGSNAT with three injections in one hemisphere. CONCLUSIONS: Despite variabilities in volume and titre, catheter design may be critical for efficient brain delivery. These data help inform a clinical trial for MPSIIIC.