Catch-Up Saccades in Vestibular Hypofunction: A Contribution of the Cerebellum?

Long-term deficits of the vestibulo-ocular reflex (VOR) elicited by head rotation can be partially compensated by catch-up saccades (CuS). These saccades are initially visually guided, but their latency can greatly decrease resulting in short latency CuS (SL-CuS). It is still unclear what triggers these CuS and what are the underlying neural circuits. In this study, we aimed at evaluating the impact of cerebellar pathology on CuS by comparing their characteristics between two groups of patients with bilateral vestibular hypofunction, with or without additional cerebellar dysfunction. We recruited 12 patients with both bilateral vestibular hypofunction and cerebellar dysfunction (BVH-CD group) and 12 patients with isolated bilateral vestibular hypofunction (BVH group). Both groups were matched for age and residual VOR gain. Subjects underwent video head impulse test recording of the horizontal semicircular canals responses as well as recording of visually guided saccades in the step, gap, and overlap paradigms. Latency and gain of the different saccades were calculated. The mean age for BVH-CD and BVH was, respectively, 67.8 and 67.2 years, and the mean residual VOR gain was, respectively, 0.24 and 0.26. The mean latency of the first catch-up saccade was significantly longer for the BVH-CD group than that for the BVH group (204 ms vs 145 ms, p < 0.05). There was no significant difference in the latency of visually guided saccades between the two groups, for none of the three paradigms. The gain of covert saccades tended to be lower in the BVH-CD group than in BVH group (t test; p = 0.06). The mean gain of the 12° or 20° visually guided saccades were not different in both groups. Our results suggest that the cerebellum plays a role in the generation of compensatory SL-CuS observed in BVH patients.

Engineered phage with antibacterial CRISPR-Cas selectively reduce E. coli burden in mice.

Antibiotic treatments have detrimental effects on the microbiome and lead to antibiotic resistance. To develop a phage therapy against a diverse range of clinically relevant Escherichia coli, we screened a library of 162 wild-type (WT) phages, identifying eight phages with broad coverage of E. coli, complementary binding to bacterial surface receptors, and the capability to stably carry inserted cargo. Selected phages were engineered with tail fibers and CRISPR-Cas machinery to specifically target E. coli. We show that engineered phages target bacteria in biofilms, reduce the emergence of phage-tolerant E. coli and out-compete their ancestral WT phages in coculture experiments. A combination of the four most complementary bacteriophages, called SNIPR001, is well tolerated in both mouse models and minipigs and reduces E. coli load in the mouse gut better than its constituent components separately. SNIPR001 is in clinical development to selectively kill E. coli, which may cause fatal infections in hematological cancer patients.

Real-world evidence for ixekizumab in the treatment of psoriasis and psoriatic arthritis: literature review 2016-2021.

OBJECTIVES: To describe the results of a structured literature review of real-world outcomes with ixekizumab in patients with psoriasis (PsO) and/or psoriatic arthritis (PsA). METHODS: Literature databases, conference proceedings and additional sources were searched for relevant publications. Real-world studies of ≥25 ixekizumab-treated patients with PsO and/or PsA were included. Data on clinical effectiveness, treatment persistence/patterns, economic outcomes, patient-reported outcomes (PROs) and safety were extracted. RESULTS: Fifty-one publications were included. Most studies focused on patients with PsO, and the number of publications with a focus on PROs was low. Studies of treatment patterns found that in general, ixekizumab had similar or better persistence versus other biologics, and rates or risk of switching similar to or less than comparator drugs. Adherence to ixekizumab was high, and patients were less likely to discontinue ixekizumab than other biologics. Ixekizumab was effective in the real world, with a safety profile consistent with that reported in clinical trials. CONCLUSIONS: Real-world use of ixekizumab in PsO and PsA is effective and safe, with generally high treatment persistence and adherence. Further work is required to determine the impact of ixekizumab on PROs in PsO, and to gather more data on real-world use of ixekizumab in PsA.

Patient Characteristics and Treatment Patterns in European Pediatric Patients with Psoriasis: A Real-World, Cross-Sectional Study.

INTRODUCTION: This study evaluated patient characteristics and treatment patterns according to weight in pediatric patients with psoriasis in a real-world setting. METHODS: Primary care and specialist physicians treating pediatric patients with psoriasis aged 6-17 years in five European countries were surveyed in the 2019-2020 Adelphi Real World Pediatric Psoriasis Disease Specific Programme. At least two patients with current or previous biologic use were included per physician. Patient characteristics and treatment patterns were analyzed overall and for patients weighing 25-50 kg or more than 50 kg. RESULTS: Data from 772 patients weighing 25-50 kg and 1147 weighing more than 50 kg were analyzed. Median age at diagnosis was significantly less in lighter than heavier patients (10.0 vs. 14.0 years; p < 0.001), as was median disease duration (2.2 vs. 3.0 years; p < 0.001). Topical treatments were prescribed in 59.0% of patients overall (70.3% of lighter and 51.4% of heavier patients; p < 0.001), and were used to treat mild rather than moderate-to-severe psoriasis. Conventional systemic use was low (10.8% of patients overall) and predominantly for moderate-to-severe psoriasis. In this biologic-enriched sample, most biologics (78.2%) were prescribed in older (> 13 years) patients. Biologic use increased with line of therapy (6.6% of first-line, 18.0% of second-line, 33.7% of third-line, 44.7% of fourth-line treatments). CONCLUSION: Biologics are predominantly prescribed in older (> 13 years) and heavier (> 50 kg) patients, with little first- or second-line use. The low use of biologics in European pediatric patients with psoriasis may represent an unmet treatment need, as topical or conventional systemic agents remain the main treatment option for moderate or severe psoriasis in these patients through the treatment pathway.

This study looked into types of treatments according to body weight in children with psoriasis, since approved dosing regimens for some treatments are based on body weight. Primary care and specialist physicians treating children with psoriasis aged 6­17 years in five European countries completed a survey. Patient information for those receiving specific types of psoriasis treatments were collected. Of the children included, 772 weighed 25­50 kg and 1147 weighed more than 50 kg. Most children received treatments applied to the skin, such as creams and ointments; this occurred in 70% of lighter patients and in 51% of heavier patients. Conventional treatments taken via the mouth were prescribed in a few patients (11% [overall]), while newer biologic drugs were taken to a greater extent in heavier (30%) than lighter (16%) patients. Most biologics (78%) were prescribed in older (> 13 years) patients. Biologic use increased with the number of failed previous treatments, comprising 7%, 18%, 34%, and 45% of first, second, third, and fourth treatments, respectively. We conclude that children with psoriasis who are treated with biologic drugs are predominantly older and heavier, and have more severe psoriasis. Prescriptions for biologics are given after many other treatments have been tried.

Burden of Moderate to Severe Atopic Dermatitis in Adults from France, Italy, and the UK: Patient-Reported Outcomes and Treatment Patterns.

INTRODUCTION: Moderate to severe atopic dermatitis (AD) is associated with a significant disease burden, impacting sleep, quality of life, and treatment needs. The aim of this study was to characterize disease burden and treatment patterns for adults with moderate to severe AD in three European countries: France, Italy, and the UK. METHODS: This retrospective analysis of adult patients with moderate to severe AD in Europe used medical records and physician/patient survey data collected in August 2019 to April 2020. Demographic and baseline disease characteristics, information on current comorbidities, disease flares, and current and previous treatments were collected by the physician. Patient-perceived burden was assessed using patient-reported outcome (PRO) questionnaires, which were completed on a voluntary basis and included the following instruments: Patient-Oriented Eczema Measure (POEM), Dermatology Life Quality Index (DLQI), EuroQol five-dimensional (EQ-5D), and Work Productivity and Activity Impairment (WPAI). Disease severity was subjectively assessed by physicians and was based on their own definition of the terms mild, moderate, and severe. Data were analyzed descriptively. RESULTS: The physician-reported sample included 912 patients with moderate to severe disease from France (n = 314), Italy (n = 309), and the UK (n = 289); approximately 30% of patients provided PRO data. Across these countries, 22-41% of patients reported current flares; mean POEM and DLQI scores were 10.6-13.1 and 9.5-11.1, respectively, indicating a high disease burden. However, systemic therapy use was low (e.g., conventional systemics were used by 18-24% of patients). Physician-assessed disease severity did not fully align with EASI scores, indicating that factors in addition to skin signs are impacting AD severity. CONCLUSION: Patients with moderate to severe AD report significant disease burden, highlighting unmet treatment needs, particularly with respect to the underuse of systemic treatments despite AD being a systemic disease and the associated disease burden.

Substantial restoration of night vision in adult mice with congenital stationary night blindness.

Complete congenital stationary night blindness (cCSNB) due to mutations in TRPM1, GRM6, GPR179, NYX, or leucine-rich repeat immunoglobulin-like transmembrane domain 3 (LRIT3) is an incurable inherited retinal disorder characterized by an ON-bipolar cell (ON-BC) defect. Since the disease is non-degenerative and stable, treatment could theoretically be administrated at any time in life, making it a promising target for gene therapy. Until now, adeno-associated virus (AAV)-mediated therapies lead to significant functional improvements only in newborn cCSNB mice. Here we aimed to restore protein localization and function in adult Lrit3 -/ - mice. LRIT3 localizes in the outer plexiform layer and is crucial for TRPM1 localization at the dendritic tips of ON-BCs and the electroretinogram (ERG)-b-wave. AAV2-7m8-Lrit3 intravitreal injections were performed targeting either ON-BCs, photoreceptors (PRs), or both. Protein localization of LRIT3 and TRPM1 at the rod-to-rod BC synapse, functional rescue of scotopic responses, and ON-responses detection at the ganglion cell level were achieved in a few mice when ON-BCs alone or both PRs and ON-BCs, were targeted. More importantly, a significant number of treated adult Lrit3 -/- mice revealed an ERG b-wave recovery under scotopic conditions, improved optomotor responses, and on-time ON-responses at the ganglion cell level when PRs were targeted. Functional rescue was maintained for at least 4 months after treatment.

Restoration of mGluR6 Localization Following AAV-Mediated Delivery in a Mouse Model of Congenital Stationary Night Blindness.

Purpose: Complete congenital stationary night blindness (cCSNB) is an incurable inherited retinal disorder characterized by an ON-bipolar cell (ON-BC) defect. GRM6 mutations are the third most prevalent cause of cCSNB. The Grm6-/- mouse model mimics the human phenotype, showing no b-wave in the electroretinogram (ERG) and a loss of mGluR6 and other proteins of the same cascade at the outer plexiform layer (OPL). Our aim was to restore protein localization and function in Grm6-/- adult mice targeting specifically ON-BCs or the whole retina. Methods: Adeno-associated virus-encoding Grm6 under two different promoters (GRM6-Grm6 and CAG-Grm6) were injected intravitreally in P15 Grm6-/- mice. ERG recordings at 2 and 4 months were performed in Grm6+/+, untreated and treated Grm6-/- mice. Similarly, immunolocalization studies were performed on retinal slices before or after treatment using antibodies against mGluR6, TRPM1, GPR179, RGS7, RGS11, Gß5, and dystrophin. Results: Following treatment, mGluR6 was localized to the dendritic tips of ON-BCs when expressed with either promoter. The relocalization efficiency in mGluR6-transduced retinas at the OPL was 2.5% versus 11% when the GRM6-Grm6 and CAG-Grm6 were used, respectively. Albeit no functional rescue was seen in ERGs, relocalization of TRPM1, GPR179, and Gß5 was also noted using both constructs. The restoration of the localization of RGS7, RGS11, and dystrophin was more obvious in retinas treated with GRM6-Grm6 than in retinas treated with CAG-Grm6. Conclusions: Our findings show the potential of treating cCSNB with GRM6 mutations; however, it appears that the transduction rate must be improved to restore visual function.

Gene Therapy for Parkinson's Disease: Preclinical Evaluation of Optimally Configured TH:CH1 Fusion for Maximal Dopamine Synthesis.

A recent phase I-II, open-label trial of ProSavin, a lentiviral vector delivering the key enzymes in the dopamine biosynthetic pathway to non-dopaminergic striatal neurons, demonstrated safety and improved motor function in parkinsonian patients. However, the magnitude of the effect suggested that optimal levels of dopamine replacement may not have been achieved. OXB-102, a lentiviral vector with an optimized expression cassette for dopamine biosynthesis, has been shown to achieve a significantly higher dopamine yield than ProSavin. We assessed the efficacy of OXB-102 in the MPTP macaque model of Parkinson's disease (PD). At 6 months post-vector administration, all treated animals showed significant improvements in clinical scores and spontaneous locomotor activity compared to controls, with the highest recovery observed in the OXB-102 high-dose (HD) group. Positron emission tomography quantification of 6-[18F]-fluoro-L-m-tyrosine uptake showed a significant increase in amino acid decarboxylase activity for all treated animals, compared with controls, where the OXB-102 HD group showed the highest level of dopaminergic activity. A toxicology study in macaques demonstrated that the vector was safe and well tolerated, with no associated clinical or behavioral abnormalities and no immune response mounted against any transgene products. Overall, these data support the further clinical development of OXB-102 for the treatment of PD.

Optogenetic Light Sensors in Human Retinal Organoids.

Optogenetic technologies paved the way to dissect complex neural circuits and monitor neural activity using light in animals. In retinal disease, optogenetics has been used as a therapeutic modality to reanimate the retina after the loss of photoreceptor outer segments. However, it is not clear today which ones of the great diversity of microbial opsins are best suited for therapeutic applications in human retinas as cell lines, primary cell cultures and animal models do not predict expression patterns of microbial opsins in human retinal cells. Therefore, we sought to generate retinal organoids derived from human induced pluripotent stem cells (hiPSCs) as a screening tool to explore the membrane trafficking efficacy of some recently described microbial opsins. We tested both depolarizing and hyperpolarizing microbial opsins including CatCh, ChrimsonR, ReaChR, eNpHR 3.0, and Jaws. The membrane localization of eNpHR 3.0, ReaChR, and Jaws was the highest, likely due to their additional endoplasmic reticulum (ER) release and membrane trafficking signals. In the case of opsins that were not engineered to improve trafficking efficiency in mammalian cells such as CatCh and ChrimsonR, membrane localization was less efficient. Protein accumulation in organelles such as ER and Golgi was observed at high doses with CatCh and ER retention lead to an unfolded protein response. Also, cytoplasmic localization was observed at high doses of ChrimsonR. Our results collectively suggest that retinal organoids derived from hiPSCs can be used to predict the subcellular fate of optogenetic proteins in a human retinal context. Such organoids are also versatile tools to validate other gene therapy products and drug molecules.

Mass spectrometry analysis of intact Francisella bacteria identifies lipid A structure remodeling in response to acidic pH stress.

Structural modification of lipid A, the lipid anchor of LPS, is one of the strategies used by Gram-negative bacteria to evade host innate immunity. Francisella tularensis is a human pathogen that infects and replicates within phagocytic cells. It produces an atypical lipid A, whose structure precludes an efficient recognition by both innate immune players, TLR4 and cationic antimicrobial peptides. Interestingly, a recent report indicates that the lipid A of Francisella (LVS vaccinal strain) undergoes polar modifications when bacteria are grown in human macrophages as compared to in broth. To characterize the structural modifications of lipid A that may be induced intracellularly, Francisella novicida, a surrogate strain for the highly virulent F. tularensis, was submitted to different stress conditions mimicking the harsh environment encountered in the macrophages. To analyze lipid A directly from intact bacteria without any chemical treatment or purification steps, we used a rapid and sensitive MALDI-TOF mass spectrometry approach. Among the many conditions tested, only bacteria exposure to acidic pHs (from 6 to 5) induced a change in lipid A structure. These changes were characterized by an increase in the relative abundance of molecular species bearing an additional hexose unit on the diglucosamine backbone, similar to species present when bacteria are grown under reduced environmental temperature. This lipid A glyco-form, which is observed in trace amounts in normal in vitro growth conditions at 37 °C, may contribute to the intracellular parasitism of macrophages by Francisella.

Protein O-mannosylation deficiency increases LprG-associated lipoarabinomannan release by Mycobacterium tuberculosis and enhances the TLR2-associated inflammatory response.

Protein O-mannosylation is crucial for the biology of Mycobacterium tuberculosis but the key mannosylated protein(s) involved and its(their) underlying function(s) remain unknown. Here, we demonstrated that the M. tuberculosis mutant (Δpmt) deficient for protein O-mannosylation exhibits enhanced release of lipoarabinomannan (LAM) in a complex with LprG, a lipoprotein required for LAM translocation to the cell surface. We determined that LprG is O-mannosylated at a unique threonine position by mass spectrometry analyses of the purified protein. However, although replacement of this amino acid by an alanine residue completely abolished LprG O-mannosylation, the increased release of the LAM/LprG complex was preserved. We found that the increased secretion of this complex is due to enhanced LAM production in the Δpmt M. tuberculosis and M. smegmatis mutants relative to their wild-type counterparts. This abnormal release of LAM/LprG has functional consequences on the induction of inflammatory responses and provides a possible explanation for the reduced virulence of the M. tuberculosis Δpmt mutant.