PSMF1 variants cause a phenotypic spectrum from early-onset Parkinson's disease to perinatal lethality by disrupting mitochondrial pathways.

Dissecting biological pathways highlighted by Mendelian gene discovery has provided critical insights into the pathogenesis of Parkinson's disease (PD) and neurodegeneration. This approach ultimately catalyzes the identification of potential biomarkers and therapeutic targets. Here, we identify PSMF1 as a new gene implicated in PD and childhood neurodegeneration. We find that biallelic PSMF1 missense and loss-of-function variants co-segregate with phenotypes from early-onset PD and parkinsonism to perinatal lethality with neurological manifestations across 15 unrelated pedigrees with 22 affected subjects, showing clear genotype-phenotype correlation. PSMF1 encodes the proteasome regulator PSMF1/PI31, a highly conserved, ubiquitously expressed partner of the 20S proteasome and neurodegeneration-associated F-box-O 7 and valosin-containing proteins. We demonstrate that PSMF1 variants impair mitochondrial membrane potential, dynamics and mitophagy in patient-derived fibroblasts. Additionally, we develop models of psmf1 knockdown Drosophila and Psmf1 conditional knockout mouse exhibiting age-dependent motor impairment, with diffuse gliosis in mice. These findings unequivocally link defective PSMF1 to early-onset PD and neurodegeneration and suggest mitochondrial dysfunction as a mechanistic contributor.

Mesophotic zone as buffer for biodiversity protection: A promising opportunity to enhance MPA effectiveness.

Coastal areas conservation strategies often left deeper habitats, such as mesophotic ones, unprotected and exposed to anthropogenic activities. In this context, an approach for including the mesophotic zone inside protection plans is proposed, considering 27 Italian Marine Protected Areas (MPAs) as a model. MPAs were classified considering their bathymetries, exposure to marine heat waves (MHWs), mass mortality events (MMEs) and, using a local ecological knowledge (LEK) approach, the estimated resilience of certain sessile species after MMEs. Only 8 MPAs contained considerable mesophotic areas, with stronger MHWs mainly occurring in shallower MPAs, and MMEs mostly affecting coralligenous assemblages. Even with only a 10% response rate, the LEK approach provided useful information on the resilience of certain species, allowing us to suggest that the presence of nearby mesophotic areas can help shallower habitats facing climate change, thus making the "deep refugia" hypothesis, usually related to tropical habitats, applicable also for the Mediterranean Sea.

HIV-related public stigma in the era of "Undetectable = Untransmittable": a population-based study in Hong Kong.

BACKGROUND: While global efforts are increasingly relying upon biomedical advancements such as antiretroviral therapy and pre-exposure prophylaxis (PrEP) to end the HIV epidemic, HIV-related stigma remains a concern. This study aimed to assess the general public's awareness and perception of "Undetectable = Untransmittable" (U = U) and PrEP, and the patterns of public stigma towards people living with HIV (PLWH) and their determinants in an Asian Pacific city. METHODS: A population-based, self-administrated online survey was conducted between 10-20 March 2023. All adults aged ≥ 18 years and currently living in Hong Kong were eligible. Participants' socio-demographic characteristics, awareness and perception of U = U and PrEP, as well as HIV-related stigma drivers, experience and practices were collected. Latent class analysis was used to delineate population subgroups based on their stigma profiles as reflected by 1.) fear of infection, 2.) concern about socioeconomic ramification of the disease, 3.) social norm enforcement, 4.) perceived stigma in the community, and 5.) stigmatising behaviours and discriminatory attitudes. Memberships of identified subgroups were then correlated with sociodemographic factors, awareness and perception of U = U and PrEP, using multinominal logistic regression. RESULTS: Responses from a total of 3070 participants (55% male; 79% aged 18-54) were analysed. A majority, 69% and 81%, indicated that they had never heard of U = U and PrEP respectively, and only 39-40% of participants perceived these to be effective in protection from HIV. Four distinct subgroups were identified, namely "Low stigma" (37%), "Modest stigma" (24%), "Moderate stigma" (24%), and "High stigma" (15%). Compared with "Low stigma", lack of awareness of and/or negative perceptions towards U = U and/or PrEP, not knowing any PLWH were associated with increased odds of higher stigma group membership. Lower educational level and not in employment were associated with increased odds of membership in "Moderate stigma" and "High stigma". While older people were more likely to belong to "High stigma", female were more likely to belong to "Moderate stigma". "Modest stigma" included more younger people who were economically active. CONCLUSION: Two-thirds of participants endorsed modest-to-high HIV-related stigma, suggesting the prevalence of HIV-related stigma was high among the general population in Hong Kong. Tailored interventions targeting specific stigma drivers and manifestations of individuals as reflected from the stigma profiles of distinct subgroups could form an important strategy for stigma reduction.

Coherence measurements of polaritons in thermal equilibrium reveal a power law for two-dimensional condensates.

We have created a spatially homogeneous polariton condensate in thermal equilibrium, up to very high condensate fraction. Under these conditions, we have measured the coherence as a function of momentum and determined the total coherent fraction of this boson system from very low density up to density well above the condensation transition. These measurements reveal a consistent power law for the coherent fraction as a function of the total density over nearly three orders of its magnitude. The same power law is seen in numerical simulations solving the two-dimensional Gross-Pitaevskii equation for the equilibrium coherence.

A scoping review of the influence of clinical contaminants on bond strength in direct adhesive restorative procedures.

OBJECTIVE: Clinical contamination during direct adhesive restorative procedures can affect various adhesive interfaces differently and contribute to bulk failure of the restorations. This review aims to summarise the current knowledge on the influence of a variety of clinical contaminants on the bond strength at various adhesive interfaces during adhesive restorative procedures and identify gaps in the literature for future research. DATA AND SOURCES: An electronic database search was performed in PubMed and EMBASE to identify articles that investigated the influence of contaminants on direct restorative bonding procedures. A data-charting form was developed by two researchers to capture the key characteristics of each eligible study. STUDY SELECTION: The initial search yielded 1,428 articles. Fifty-seven articles published between 1 Jan 2007 and 25 Oct 2023 were included in the final review. Thirty-three of the articles examined the influence of saliva contamination, twelve articles examined the influence of blood contamination, and twenty-five articles examined the influence of other contaminants. CONCLUSION: Saliva contamination exerted less influence on the decrease in bond strength when self-etch systems were used, compared to when etch-and-rinse systems were used. Blood contamination adversely affected the bond strength at the interface between resin composite and dentine, and resin composite and resin-modified glass ionomer cement. Treating contaminated surfaces with water spray for 10-30 s followed by air drying could be effective in recovering bond strength following saliva and blood contamination. CLINICAL SIGNIFICANCE: This scoping review provides a valuable overview of the range of potential clinical contaminants that can influence the bond strength between different interfaces in direct adhesive restorative procedures. Additionally, it identifies potential decontamination protocols that can be followed to restore and enhance bond strength.

Diet Pattern Analysis in Alzheimer's Disease Implicates Gender Differences in Folate-B12-Homocysteine Axis on Cognitive Outcomes.

BACKGROUND & AIMS: Low plasma B12 and folate levels or hyperhomocysteinemia are related to cognitive impairment. This study explores the relationships among diet pattern, blood folate-B12-homocysteine levels, and cognition measurement in Alzheimer's disease (AD) while exploring whether a gender effect may exist. METHODS: This cross-sectional study enrolled 592 AD patients (246 males, 346 females) and the demographic data, blood biochemical profiles, Mini-Mental State Examination (MMSE), and a Food Frequency Questionnaire (FFQ) for quantitative assessment of dietary frequency were collected. Structural Equation Modeling (SEM) was employed to explore the associations among dietary patterns, blood profiles, and cognition. A least absolute shrinkage and selection operator regression model, stratified by gender, was constructed to analyze the weighting of possible confounders. RESULTS: Higher MMSE scores were related to higher frequencies of coffee/tea and higher educational levels, body mass index, and younger age. The SEM model revealed a direct influence of dietary frequencies (skimmed milk, thin pork, coffee/tea) and blood profiles (homocysteine, B12, and folate) on cognitive outcomes. At the same time, the influence of dietary pattern on cognition was not mediated by folate-B12-homocysteine levels. In males, a direct influence on the MMSE is attributed to B12, while in females, homocysteine is considered a more critical factor. CONCLUSIONS: Dietary patterns and blood profiles are both associated with cognitive domains in AD, and there are gender differences in the associations of dietary patterns and the levels of B12 and homocysteine. To enhance the quality of dietary care and nutritional status for individuals with dementia, our study results still require future validations with multi-center and longitudinal studies.

Enhancing the Spermidine Synthase-Based Polyamine Biosynthetic Pathway to Boost Rapid Growth in Marine Diatom Phaeodactylum tricornutum.

Diatoms, efficient carbon capture organisms, contribute to 20% of global carbon fixation and 40% of ocean primary productivity, garnering significant attention to their growth. Despite their significance, the synthesis mechanism of polyamines (PAs), especially spermidine (Spd), which are crucial for growth in various organisms, remains unexplored in diatoms. This study reveals the vital role of Spd, synthesized through the spermidine synthase (SDS)-based pathway, in the growth of the diatom Phaeodactylum tricornutum. PtSDS1 and PtSDS2 in the P. tricornutum genome were confirmed as SDS enzymes through enzyme-substrate selectivity assays. Their distinct activities are governed primarily by the Y79 active site. Overexpression of a singular gene revealed that PtSDS1, PtSDS2, and PtSAMDC from the SDS-based synthesis pathway are all situated in the cytoplasm, with no significant impact on PA content or diatom growth. Co-overexpression of PtSDS1 and PtSAMDC proved essential for elevating Spd levels, indicating multifactorial regulation. Elevated Spd content promotes diatom growth, providing a foundation for exploring PA functions and regulation in diatoms.

Latent Heterogeneity of Online Sexual Experiences and Associations With Sexual Risk Behaviors and Behavioral Health Outcomes in Chinese Young Adults: Cross-Sectional Study.

BACKGROUND: Online sexual experiences (OSEs) are becoming increasingly common in young adults, but existing papers have reported only on specific types of OSEs and have not shown the heterogeneous nature of the repertoire of OSEs. The use patterns of OSEs remain unclear, and the relationships of OSEs with sexual risk behaviors and behavioral health outcomes have not been evaluated. OBJECTIVE: This study aimed to examine the latent heterogeneity of OSEs in young adults and the associations with sexual risk behaviors and behavioral health outcomes. METHODS: The 2021 Youth Sexuality Study of the Hong Kong Family Planning Association phone interviewed a random sample of 1205 young adults in Hong Kong in 2022 (male sex: 613/1205, 50.9%; mean age 23.0 years, SD 2.86 years) on lifetime OSEs, demographic and family characteristics, Patient Health Questionnaire-4 (PHQ-4) scores, sex-related factors (sexual orientation, sex knowledge, and sexual risk behaviors), and behavioral health outcomes (sexually transmitted infections [STIs], drug use, and suicidal ideation) in the past year. Sample heterogeneity of OSEs was analyzed via latent class analysis with substantive checking of the class profiles. Structural equation modeling was used to examine the direct and indirect associations between the OSE class and behavioral health outcomes via sexual risk behaviors and PHQ-4 scores. RESULTS: The data supported 3 latent classes of OSEs with measurement invariance by sex. In this study, 33.1% (398/1205), 56.0% (675/1205), and 10.9% (132/1205) of the sample were in the abstinent class (minimal OSEs), normative class (occasional OSEs), and active class (substantive OSEs), respectively. Male participants showed a lower prevalence of the abstinent class (131/613, 21.4% versus 263/592, 44.4%) and a higher prevalence of the active class (104/613, 17.0% versus 28/592, 4.7%) than female participants. The normative class showed significantly higher sex knowledge than the other 2 classes. The active class was associated with male sex, nonheterosexual status, higher sex desire and PHQ-4 scores, and more sexual risk behaviors than the other 2 classes. Compared with the nonactive (abstinent and normative) classes, the active class was indirectly associated with higher rates of STIs (absolute difference in percentage points [Δ]=4.8%; P=.03) and drug use (Δ=7.6%; P=.001) via sexual risk behaviors, and with higher rates of suicidal ideation (Δ=2.5%; P=.007) via PHQ-4 scores. CONCLUSIONS: This study provided the first results on the 3 (abstinent, normative, and active) latent classes of OSEs with distinct profiles in OSEs, demographic and family characteristics, PHQ-4 scores, sex-related factors, and behavioral health outcomes. The active class showed indirect associations with higher rates of STIs and drug use via sexual risk behaviors and higher rates of suicidal ideation via PHQ-4 scores than the other 2 classes. These results have implications for the formulation and evaluation of targeted interventions to help young adults.

Genetic Modification of Aurantiochytrium sp. 18W-13a for Enhancement of Proteolytic Activity by Heterologous Expression of Extracellular Proteases.

A marine thraustochytrid, Aurantiochytrium, is a promising organism to produce docosahexaenoic acid (DHA) and squalene. Utilization of inexpensive substances such as proteins in wastes and by-products from the food industry for cultivation is a considerable option to reduce production cost; however, the proteolytic ability of Aurantiochytrium spp. is low compared to taxonomically close Shizochytrium aggregatum. We previously identified extracellular protease (extracellular protease 1, EP1) in S. aggregatum ATCC 28209 from the supernatant of the culture and found that a similar protease gene (EP2) was located downstream of the EP1 gene. In the present study, we created the transformants expressing SaEP1 and/or SaEP2 to enhance the proteolytic ability of Aurantiochytrium sp. 18W-13a strain and cultivated them in the medium containing casein as a test protein substrate. Through SDS-PAGE analysis, we confirmed that casein in the supernatant was more efficiently degraded by the transformants than the wild type, suggesting that the expressed protease(s) were properly expressed and excreted. After 4-day cultivation in the casein medium, the value of optical density at 660 nm and the cell number in the culture of the transformant that expressed both SaEP1 and SaEP2 (designated as EP12 strain) showed 1.48- and 1.38-fold higher than those of wild type, respectively. The DHA and squalene yield of the EP12 strain were respectively 158.3 and 0.23 mg L-1, and these values were 1.42- and 2.01-fold higher than those of wild type, respectively, suggesting that the EP12 created in the present study is a favorable strain for the cultivation using protein-containing medium.

Amino acid substitution L232F in non-structural protein 6 identified as a possible human-adaptive mutation in clade B MERS coronaviruses.

IMPORTANCE: Viral host adaptation plays an important role in inter-species transmission of coronaviruses and influenza viruses. Multiple human-adaptive mutations have been identified in influenza viruses but not so far in MERS-CoV that circulates widely in dromedary camels in the Arabian Peninsula leading to zoonotic transmission. Here, we analyzed clade B MERS-CoV sequences and identified an amino acid substitution L232F in nsp6 that repeatedly occurs in human MERS-CoV. Using a loss-of-function reverse genetics approach, we found the nsp6 L232F conferred increased viral replication competence in vitro, in cultures of the upper human respiratory tract ex vivo, and in lungs of mice infected in vivo. Our results showed that nsp6 L232F may be an adaptive mutation associated with zoonotic transmission of MERS-CoV. This study highlighted the capacity of MERS-CoV to adapt to transmission to humans and also the need for continued surveillance of MERS-CoV in camels.

Enfortumab vedotin and pembrolizumab as monotherapies and combination treatment in locally advanced or metastatic urothelial carcinoma: A narrative review.

Background: Bladder cancer is the 10th most common cancer globally. The majority of bladder cancers are urothelial carcinomas (UCs), which, if locally advanced or metastatic, carry poor long-term prognosis. Cancer cells can evade the immune system by expressing the programmed cell death ligand 1 protein (PD-L1). Programmed cell death ligand 1 protein binds to programmed cell death protein 1 (PD-1) on T cells, inhibiting their antitumor action. Bladder tumor cells also overexpress nectin-4, a cell adhesion polypeptide that contributes to metastasis, worsening prognosis. Current platinum-based chemotherapy treatments are suboptimal. This review aimed to assess novel treatments for locally advanced or metastatic UC that specifically target PD-L1 or nectin-4, namely, the PD-1 inhibitor pembrolizumab and the anti-nectin-4 antibody-drug conjugate enfortumab vedotin (EV). Materials and methods: Relevant English-language peer-reviewed articles and conference abstracts from the last 5 years were identified through MEDLINE and EMBASE database searches. A narrative review was performed, with key results outlined below. Results: Pembrolizumab was demonstrated to be superior to chemotherapy as a second-line treatment for platinum-unresponsive participants in the KEYNOTE-045 trial, resulting in its Food and Drug Administration (FDA) approval. Enfortumab vedotin therapy resulted in superior outcomes compared with chemotherapy in the EV-301 trial, resulting in FDA approval for its use for patients with locally advanced or metastatic UC who had previously undergone treatment with platinum-based chemotherapy and PD-1/PD-L1 inhibitors. Positive preliminary results for pembrolizumab and EV combination therapy have led to FDA approval in patients with locally advanced or metastatic UC who are not eligible for platinum chemotherapy. Conclusions: Pembrolizumab and EV represent novel treatment options for patients with locally advanced or metastatic UC with documented superior outcomes and tolerability as compared with standard chemotherapy.

Quantitative Textural and Rheological Data on Different Levels of Texture-Modified Food and Thickened Liquids Classified Using the International Dysphagia Diet Standardisation Initiative (IDDSI) Guideline.

Diet modification is a common compensation strategy to promote swallowing safety in patients with swallowing difficulties. The International Dysphagia Diet Standardisation Initiative (IDDSI) guideline provides qualitative descriptions on texture-modified food and thickened liquid. This study aimed to establish quantitative textural and rheological data on different IDDSI levels based on common Chinese ingredients and dishes. Textural and rheological properties of 226 samples of various food textures and 93 samples of various liquid consistencies were obtained using a texture profile analysis (TPA) and viscometer, respectively. The establishment of such quantitative data can be used for future texture-modified food product development and research purposes.

Safety of sodium-glucose transporter 2 (SGLT-2) inhibitors in patients with type 2 diabetes: a meta-analysis of cohort studies.

Aims: This study aimed to investigate the association between the use of sodium-glucose transporter 2 inhibitors (SGLT-2i) and the risk of diabetic ketoacidosis (DKA), lower limb amputation (LLA), urinary tract infections (UTI), genital tract infections (GTI), bone fracture, and hypoglycemia in cohort studies. Methods: A systematic search was conducted in the PubMed and Embase databases to identify cohort studies comparing the safety of SGLT-2i versus other glucose-lowering drugs (oGLD) in patients with type 2 diabetes mellitus (T2DM). The quality of the studies was assessed using the Newcastle-Ottawa Scale. Primary endpoints were DKA and LLA, while secondary endpoints included UTI, GTI, bone fracture, and hypoglycemia. Hazard ratios (HR) with 95% confidence intervals (CI) were calculated. Results: A total of 9,911,454 patients from 40 cohort studies were included in the analysis. SGLT-2i use was associated with a higher risk of DKA (HR: 1.21, 95% CI: 1.07-1.38, p = 0.003) and GTI (HR: 2.72, 95% CI: 2.48-2.98, p < 0.01). However, it was not associated with an increased risk of LLA (HR: 1.06, 95% CI: 0.92-1.23, p = 0.42), UTI (HR: 0.99, 95% CI: 0.89-1.10, p = 0.83), or bone fracture (HR: 0.99, 95% CI: 0.94-1.04, p = 0.66). Furthermore, SGLT-2i was associated with a reduced risk of hypoglycemia. Furthermore, compared to dipeptidyl peptidase 4 inhibitors, SGLT-2i as a class and individually was associated with an increased risk of DKA. Canagliflozin specifically increased the risk of LLA (HR: 1.19, 95% CI: 1.04-1.36, p = 0.01). The subgroup analysis suggested that SGLT-2i increased the risk of LLA among patients with a history of cardiovascular disease. Conclusion: SGLT-2i versus oGLD was associated with a similar occurrence of LLA, UTI, and bone fracture. However, SGLT-2i was associated with a higher risk of DKA and GTI than oGLD. These findings provide valuable information on the safety profile of SGLT-2i in patients with T2DM and can help inform clinical decision-making.

A Biomarker of Stress and Self-reported Caregiving Distress Predict Poor Quality of Life in Family Caregivers of Patients With Heart Failure.

BACKGROUND: Family caregivers are at a high risk for low quality of life due to caregiving-related stress. Caregivers' stress is commonly assessed using self-reported measures, which reflect relatively subjective and long-term stress related to caregiving, but objective biological markers of stress are rarely used for caregivers. The purposes of this study were (1) to determine whether caregiver characteristics were associated with stress assessed using a stress biomarker (serum cortisol) and a self-reported caregiving distress measure (Caregiver Burden Inventory) and (2) to determine the predictability of both stress measures for quality of life in caregivers of patients with heart failure. METHODS: Taiwanese family caregivers (N = 113; mean age, 54.5 years; 70.8% female) of patients with heart failure completed surveys including caregiving distress and quality of life measured by the Caregiver Burden Inventory and the Short Form-36 (physical and psychological well-being subscales), respectively, and provided blood samples for serum cortisol. Independent t tests, correlation, and hierarchical regression were conducted. RESULTS: Single caregivers had higher serum cortisol levels than married caregivers (P = .002). Men had significantly higher serum cortisol levels than women (P = .010), but men reported lower caregiving distress than women (P = .049). Both serum cortisol (ß = -0.32, P = .012) and caregiving distress (ß = -0.29, P = .018) were significant predictors of quality of life in the physical well-being scale while controlling for caregivers' characteristics and depressive symptoms. Serum cortisol (ß = -0.28, P = .026) and caregiving distress (ß = -0.25, P = .027) also predicted quality of life in the psychological well-being scale. CONCLUSIONS: Serum cortisol and self-reported caregiving distress have similar predictability for quality of life in family caregivers of patients with heart failure. Reducing stress and caregiving distress is critical to improving quality of life in this population.

Identification of New Antiseizure Medication Candidates in Preclinical Animal Studies.

Epilepsy is a multifactorial neurologic disease that often leads to many devastating disabilities and an enormous burden on the healthcare system. Until now, drug-resistant epilepsy has presented a major challenge for approximately 30% of the epileptic population. The present article summarizes the validated rodent models of seizures employed in pharmacological researches and comprehensively reviews updated advances of novel antiseizure candidates in the preclinical phase. Newly discovered compounds that demonstrate antiseizure efficacy in preclinical trials will be discussed in the review. It is inspiring that several candidates exert promising antiseizure activities in drug-resistant seizure models. The representative compounds consist of derivatives of hybrid compounds that integrate multiple approved antiseizure medications, novel positive allosteric modulators targeting subtype-selective γ-Aminobutyric acid type A receptors, and a derivative of cinnamamide. Although the precise molecular mechanism, pharmacokinetic properties, and safety are not yet fully clear in every novel antiseizure candidate, the adapted approaches to design novel antiseizure medications provide new insights to overcome drug-resistant epilepsy.

Apical-Out Human Airway Organoids Modeling SARS-CoV-2 Infection.

The respiratory epithelium, particularly the airway epithelium, is the primary infection site for respiratory pathogens. The apical surface of epithelial cells is constantly exposed to external stimuli including invading pathogens. Efforts have been made to establish organoid cultures to recapitulate the human respiratory tract. However, a robust and simple model with an easily accessible apical surface would benefit respiratory research. Here, we report the generation and characterization of apical-out airway organoids from the long-term expandable lung organoids that we previously established. The apical-out airway organoids morphologically and functionally recapitulated the human airway epithelium at a comparable level to the apical-in airway organoids. Moreover, apical-out airway organoids sustained productive and multicycle replication of SARS-CoV-2, and accurately recapitulated the higher infectivity and replicative fitness of the Omicron variants BA.5 and B.1.1.529 and an ancestral virus. In conclusion, we established a physiologically relevant and convenient apical-out airway organoid model for studying respiratory biology and diseases.

A natural non-synonymous single nucleotide polymorphism in GmbHLH113 negates its inhibitory effect on root hair elongation in soybean.

Root hair length (RHL) is an important character that affects nutrient acquisition in plants. The regulatory network in soybean controlling RHL is yet to be fully understood. In this study, we identified a quantitative trait locus (QTL) regulating RHL. One candidate causal gene in this QTL (GmbHLH113), preferentially expressed in root hairs, was annotated as encoding a basic helix-loop-helix transcription factor. In wild soybeans, the allelic type of GmbHLH113 with a glycine in the 13th residue, which was associated with a reduction in RHL, was shown to localize in the nucleus and activate gene transcription. Another allelic type with a single nucleotide polymorphism that resulted in a glutamate in the 13th residue is fixed in cultivated soybeans, and it lost the ability to localize to the nucleus or negatively regulate RHL. The ectopic expression of GmbHLH113 from W05 in Arabidopsis root hairs resulted in shorter RHL and reduced phosphorus (P) accumulation in shoots. Hence, a loss-of-function allele in cultivated soybeans might have been selected during domestication due to its association with a longer RHL and improved nutrient acquisition.

Establishing Bipotential Human Lung Organoid Culture System and Differentiation to Generate Mature Alveolar and Airway Organoids.

A robust in vitro model of the human respiratory epithelium, including the alveolar and the airway epithelium, is essential for understanding the biology and pathology of the human respiratory system. We previously described a protocol to derive human lung organoids from primary lung tissues. We now describe a protocol to induce bidirectional differentiation to generate mature alveolar or airway organoids. The lung organoids are consecutively expanded for over one year with high stability, while the differentiated alveolar and airway organoids morphologically and functionally simulate the human alveolar and airway epithelium to a near-physiological level. Thus, we establish a robust organoid culture system of the entire human respiratory epithelium, the first two-phase bipotential organoid culture system that enables long-term expansion and bidirectional differentiation of respiratory epithelial cells. The long-term expandable lung organoids and differentiated organoids generate a stable and renewable source of respiratory epithelial cells, enabling scientists to reconstruct and expand the human respiratory epithelium in culture dishes. The respiratory organoid system provides a unique and physiologically active in vitro model of the human respiratory epithelium for various applications, including studying respiratory viral infection, disease modeling, drug screening, and pre-clinical testing. Graphical abstract.

Human airway and nasal organoids reveal escalating replicative fitness of SARS-CoV-2 emerging variants.

The high transmissibility of SARS-CoV-2 Omicron subvariants was generally ascribed to immune escape. It remained unclear whether the emerging variants have gradually acquired replicative fitness in human respiratory epithelial cells. We sought to evaluate the replicative fitness of BA.5 and earlier variants in physiologically active respiratory organoids. BA.5 exhibited a dramatically increased replicative capacity and infectivity than B.1.1.529 and an ancestral strain wildtype (WT) in human nasal and airway organoids. BA.5 spike pseudovirus showed a significantly higher entry efficiency than that carrying WT or B.1.1.529 spike. Notably, we observed prominent syncytium formation in BA.5-infected nasal and airway organoids, albeit elusive in WT- and B.1.1.529-infected organoids. BA.5 spike-triggered syncytium formation was verified by lentiviral overexpression of spike in nasal organoids. Moreover, BA.5 replicated modestly in alveolar organoids, with a significantly lower titer than B.1.1.529 and WT. Collectively, the higher entry efficiency and fusogenic activity of BA.5 spike potentiated viral spread through syncytium formation in the human airway epithelium, leading to enhanced replicative fitness and immune evasion, whereas the attenuated replicative capacity of BA.5 in the alveolar organoids may account for its benign clinical manifestation.