Y chromosome shredding in Anopheles gambiae: Insight into the cellular dynamics of a novel synthetic sex ratio distorter.

Despite efforts to explore the genome of the malaria vector Anopheles gambiae, the Y chromosome of this species remains enigmatic. The large number of repetitive and heterochromatic DNA sequences makes the Y chromosome exceptionally difficult to fully assemble, hampering the progress of gene editing techniques and functional studies for this chromosome. In this study, we made use of a bioinformatic platform to identify Y-specific repetitive DNA sequences that served as a target site for a CRISPR/Cas9 system. The activity of Cas9 in the reproductive organs of males caused damage to Y-bearing sperm without affecting their fertility, leading to a strong female bias in the progeny. Cytological investigation allowed us to identify meiotic defects and investigate sperm selection in this new synthetic sex ratio distorter system. In addition, alternative promoters enable us to target the Y chromosome in specific tissues and developmental stages of male mosquitoes, enabling studies that shed light on the role of this chromosome in male gametogenesis. This work paves the way for further insight into the poorly characterised Y chromosome of Anopheles gambiae. Moreover, the sex distorter strain we have generated promises to be a valuable tool for the advancement of studies in the field of developmental biology, with the potential to support the progress of genetic strategies aimed at controlling malaria mosquitoes and other pest species.

Anti-CRISPR Anopheles mosquitoes inhibit gene drive spread under challenging behavioural conditions in large cages.

CRISPR-based gene drives have the potential to spread within populations and are considered as promising vector control tools. A doublesex-targeting gene drive was able to suppress laboratory Anopheles mosquito populations in small and large cages, and it is considered for field application. Challenges related to the field-use of gene drives and the evolving regulatory framework suggest that systems able to modulate or revert the action of gene drives, could be part of post-release risk-mitigation plans. In this study, we challenge an AcrIIA4-based anti-drive to inhibit gene drive spread in age-structured Anopheles gambiae population under complex feeding and behavioural conditions. A stochastic model predicts the experimentally-observed genotype dynamics in age-structured populations in medium-sized cages and highlights the necessity of large-sized cage trials. These experiments and experimental-modelling framework demonstrate the effectiveness of the anti-drive in different scenarios, providing further corroboration for its use in controlling the spread of gene drive in Anopheles.

Home-Based Adaptation to Night-Time Non-Invasive Ventilation in Patients with Amyotrophic Lateral Sclerosis: A Randomized Controlled Trial.

BACKGROUND: Initiation to Non-Invasive Ventilation (NIV) in amyotrophic lateral sclerosis (ALS) can be implemented in an inpatient or outpatient setting. AIMS: We aimed to evaluate the efficacy of adaptation (the number of needed sessions) to home-based NIV compared to an outpatient one in ALS in terms of arterial carbon dioxide (PaCO2) improvement. NIV acceptance (mean use of ≥5 h NIV per night for three consecutive nights during the adaptation trial), adherence (night-time NIV usage for ≥150 h/month), quality of life (QoL), and caregiver burden were secondary outcomes. METHODS: A total of 66 ALS patients with indications for NIV were involved in this randomized controlled trial (RCT): 34 underwent NIV initiation at home (home adaptation, HA) and 32 at multiple outpatient visits (outpatient adaptation, OA). Respiratory function tests were performed at baseline (the time of starting the NIV, T0) together with blood gas analysis, which was repeated at the end of adaptation (T1) and 2 (T2) and 6 (T3) months after T1. NIV adherence was measured at T2 and T3. Overnight cardiorespiratory polygraphy, Short Form Health Survey (SF-36), Caregiver Burden Inventory (CBI), Caregiver Burden Scale (CBS), and Zarit Burden Interview (ZBI) were performed at T0, T2, and T3. RESULTS: Fifty-eight participants completed the study. No differences were found between groups in PaCO2 at T1 (p = 0.46), T2 (p = 0.50), and T3 (p = 0.34) in acceptance (p = 0.55) and adherence to NIV at T2 and T3 (p = 0.60 and p = 0.75, respectively). At T2, the patients' QoL, assessed with SF-36, was significantly better in HA than in OA (p = 0.01), but this improvement was not maintained until T3 (p = 0.17). CONCLUSIONS: In ALS, adaptation to NIV in the patient's home is as effective as that performed in an outpatient setting regarding PaCO2, acceptance, and adherence, which emphasizes the need for further studies to understand the role of the environment concerning NIV adherence.

Early initiation of night-time NIV in an outpatient setting: a randomized non-inferiority study in ALS patients.

BACKGROUND: In patients with amyotrophic lateral sclerosis (ALS), non-invasive ventilation (NIV) is usually initiated in an in-hospital regime. AIM: We investigated if NIV initiated in an outpatient setting can be as effective in terms of patients' acceptance/adherence. We also evaluated factors predicting NIV acceptance and adherence and disease progression. DESIGN: Prospective randomized study. SETTING: Outpatient versus inpatient rehabilitation. POPULATION: ALS patients. METHODS: ALS patients were randomized to two groups for NIV initiation: outpatients versus inpatients. At baseline (T0), end of NIV trial program (T1) and after 3 months from T1 (T2), respiratory function tests, blood gas analysis, and sleep study were performed. At T1, we assessed: NIV acceptance (>4 h/night), and dyspnea symptoms (day/night) by Visual analogue scale (VAS), staff and patients' experience (how difficult NIV was to accept, how difficult ventilator was to manage, satisfaction); at T2: NIV adherence (>120 h/month) and patients' experience. RESULTS: Fifty patients participated. There were no differences in acceptance failure (P=0.733) or adherence failure (P=0.529). At T1, outpatients had longer hours of nocturnal ventilation (P<0.02), at T2 this was similar (P=0.34). Female gender and spinal onset of the disease were predictors for NIV acceptance/adherence failure. There were no between-group differences in progression of respiratory impairment, symptoms and sleep quality. CONCLUSIONS: Early outpatient initiation of NIV in ALS is as effective as inpatient initiation.