Insm1 regulates mTEC development and immune tolerance.

The expression of self-antigens in medullary thymic epithelial cells (mTECs) is essential for the establishment of immune tolerance, but the regulatory network that controls the generation and maintenance of the multitude of cell populations expressing self-antigens is poorly understood. Here, we show that Insm1, a zinc finger protein with known functions in neuroendocrine and neuronal cells, is broadly coexpressed with an autoimmune regulator (Aire) in mTECs. Insm1 expression is undetectable in most mimetic cell populations derived from mTECs but persists in neuroendocrine mimetic cells. Mutation of Insm1 in mice downregulated Aire expression, dysregulated the gene expression program of mTECs, and altered mTEC subpopulations and the expression of tissue-restricted antigens. Consistent with these findings, loss of Insm1 resulted in autoimmune responses in multiple peripheral tissues. We found that Insm1 regulates gene expression in mTECs by binding to chromatin. Interestingly, the majority of the Insm1 binding sites are co-occupied by Aire and enriched in superenhancer regions. Together, our data demonstrate the important role of Insm1 in the regulation of the repertoire of self-antigens needed to establish immune tolerance.

lhCLIP reveals the in vivo RNA-RNA interactions recognized by hnRNPK.

RNA-RNA interactions play a crucial role in regulating gene expression and various biological processes, but identifying these interactions on a transcriptomic scale remains a challenge. To address this, we have developed a new biochemical technique called pCp-biotin labelled RNA hybrid and ultraviolet crosslinking and immunoprecipitation (lhCLIP) that enables the transcriptome-wide identification of intra- and intermolecular RNA-RNA interactions mediated by a specific RNA-binding protein (RBP). Using lhCLIP, we have uncovered a diverse landscape of intermolecular RNA interactions recognized by hnRNPK in human cells, involving all major classes of noncoding RNAs (ncRNAs) and mRNA. Notably, hnRNPK selectively binds with snRNA U4, U11, and U12, and shapes the secondary structure of these snRNAs, which may impact RNA splicing. Our study demonstrates the potential of lhCLIP as a user-friendly and widely applicable method for discovering RNA-RNA interactions mediated by a particular protein of interest and provides a valuable tool for further investigating the role of RBPs in gene expression and biological processes.

Restoration of PITPNA in Type 2 diabetic human islets reverses pancreatic beta-cell dysfunction.

Defects in insulin processing and granule maturation are linked to pancreatic beta-cell failure during type 2 diabetes (T2D). Phosphatidylinositol transfer protein alpha (PITPNA) stimulates activity of phosphatidylinositol (PtdIns) 4-OH kinase to produce sufficient PtdIns-4-phosphate (PtdIns-4-P) in the trans-Golgi network to promote insulin granule maturation. PITPNA in beta-cells of T2D human subjects is markedly reduced suggesting its depletion accompanies beta-cell dysfunction. Conditional deletion of Pitpna in the beta-cells of Ins-Cre, Pitpnaflox/flox mice leads to hyperglycemia resulting from decreasing glucose-stimulated insulin secretion (GSIS) and reducing pancreatic beta-cell mass. Furthermore, PITPNA silencing in human islets confirms its role in PtdIns-4-P synthesis and leads to impaired insulin granule maturation and docking, GSIS, and proinsulin processing with evidence of ER stress. Restoration of PITPNA in islets of T2D human subjects reverses these beta-cell defects and identify PITPNA as a critical target linked to beta-cell failure in T2D.

Multiple anthropogenic stressors influence the taxonomic and functional homogenization of macroinvertebrate communities on the mainstream of an urban-agricultural river in China.

Biodiversity loss is caused by intensive human activities and threatens human well-being. However, less is known about how the combined effects of multiple stressors on the diversity of internal (alpha diversity) and multidimensional (beta diversity) communities. Here, we conducted a long-term experiment to quantify the contribution of environmental stressors (including water quality, land use, climate factors, and hydrological regimes) to macroinvertebrate communities alpha and beta diversity in the mainstream of the Songhua River, the third largest river in China, from 2012 to 2019. Our results demonstrated that the alpha and beta diversity indices showed a decline during the study period, with the dissimilarity in community composition between sites decreasing significantly, especially in the impacted river sections (upper and midstream). Despite overall improvement in water quality after management intervention, multiple human-caused stressors still have led to biotic homogenization of macroinvertebrate communities in terms of both taxonomic and functional diversities in the past decade. Our study revealed the increased human land use explained an important portion of the variation of diversities, further indirectly promoting biotic homogenization by changing the physical and chemical factors of water quality, ultimately altering assemblage ecological processes. Furthermore, the facets of diversity have distinct response mechanisms to stressors, providing complementary information from the perspective of taxonomy and function to better reflect the ecological changes of communities. Environmental filtering determined taxonomic beta diversity, and functional beta diversity was driven by the joint efforts of stressors and spatial processes. Finally, we proposed that traditional water quality monitoring alone cannot fully reveal the status of river ecological environment protection, and more importantly, we should explore the continuous changes in biodiversity over the long term. Meanwhile, our results also highlight timely control of nutrient input and unreasonable expansion of land use can better curb the ecological degradation of rivers and promote the healthy and sustainable development of floodplain ecosystems.

Epistatic genetic interactions between Insm1 and Ikzf2 during cochlear outer hair cell development.

The cochlea harbors two types of sound receptors, outer hair cells (OHCs) and inner hair cells (IHCs). OHCs transdifferentiate into IHCs in Insm1 mutants, and OHCs in Ikzf2-deficient mice are dysfunctional and maintain partial IHC gene expression. Insm1 potentially acts as a positive but indirect regulator of Ikzf2, considering that Insm1 is expressed earlier than Ikzf2 and primarily functions as a transcriptional repressor. However, direct evidence of this possibility is lacking. Here, we report the following results: first, Insm1 overexpression in IHCs leads to ectopic Ikzf2 expression. Second, Ikzf2 expression is repressed in Insm1-deficient OHCs, and forced expression of Ikzf2 mitigates the OHC abnormality in Insm1 mutants. Last, dual ablation of Insm1 and Ikzf2 generates a similar OHC phenotype as does Insm1 ablation alone. Collectively, our findings reveal the transcriptional cascade from Insm1 to Ikzf2, which should facilitate future investigation of the molecular mechanisms underlying OHC development and regeneration.

Prox2 and Runx3 vagal sensory neurons regulate esophageal motility.

Vagal sensory neurons monitor mechanical and chemical stimuli in the gastrointestinal tract. Major efforts are underway to assign physiological functions to the many distinct subtypes of vagal sensory neurons. Here, we use genetically guided anatomical tracing, optogenetics, and electrophysiology to identify and characterize vagal sensory neuron subtypes expressing Prox2 and Runx3 in mice. We show that three of these neuronal subtypes innervate the esophagus and stomach in regionalized patterns, where they form intraganglionic laminar endings. Electrophysiological analysis revealed that they are low-threshold mechanoreceptors but possess different adaptation properties. Lastly, genetic ablation of Prox2 and Runx3 neurons demonstrated their essential roles for esophageal peristalsis in freely behaving mice. Our work defines the identity and function of the vagal neurons that provide mechanosensory feedback from the esophagus to the brain and could lead to better understanding and treatment of esophageal motility disorders.

Experience of clinical nurses engaged in caring for patients with COVID-19: A qualitative systematic review and meta-synthesis.

AIMS AND OBJECTIVE: This qualitative review summarises and synthesises the available evidence on subjective experiences of clinical nurses who cared for patients with COVID-19. BACKGROUND: Nurses are first responders and play a vital role in emerging infectious disease epidemics such as the COVID-19 pandemic. In this context, they also face many difficulties and challenges related, for example to the imbalance between extensive demands and low control over work tasks. DESIGN AND METHOD: A systematic review of qualitative studies and meta-synthesis focused on the experiences of clinical nurses caring for patients with COVID-19 during the pandemic was carried out. RESULTS: A total of 279 findings were extracted, aggregated into 21 categories and combined into seven synthesised findings, namely (1) professional nursing practice during the pandemic, (2) support systems, (3) somatic sensations and psychological experiences, (4) difficulties and challenges, (5) coping strategies and behaviour, (6) impact on life, profession and values, and (7) needs and expectations for the future. CONCLUSION: Nurses encountered considerable difficulties and challenges in caring for patients with COVID-19. Nurses caring for patients with COVID-19 need more support from organisations, families and society. It is essential to explore positive coping strategies suitable for working in different cultural backgrounds. Policymakers and decision-makers should pay attention to the experiences and voices of nurses. RELEVANCE TO CLINICAL PRACTICE: It is critical for nurse managers to consider how to enhance the support system and help nurses develop adaptive coping strategies in response to COVID-19. Nurses' experiences and voices are valuable in improving health emergency response systems. PATIENT OR PUBLIC CONTRIBUTION: There was no patient or public contribution.

Topological near fields generated by topological structures.

The central idea of metamaterials and metaoptics is that, besides their base materials, the geometry of structures offers a broad extra dimension to explore for exotic functionalities. Here, we discover that the topology of structures fundamentally dictates the topological properties of optical fields and offers a new dimension to exploit for optical functionalities that are irrelevant to specific material constituents or structural geometries. We find that the nontrivial topology of metal structures ensures the birth of polarization singularities (PSs) in the near field with rich morphologies and intriguing spatial evolutions including merging, bifurcation, and topological transition. By mapping the PSs to non-Hermitian exceptional points and using homotopy theory, we extract the core invariant that governs the topological classification of the PSs and the conservation law that regulates their spatial evolutions. The results bridge singular optics, topological photonics, and non-Hermitian physics, with potential applications in chiral sensing, chiral quantum optics, and beyond photonics in other wave systems.

Optical force and torque on small particles induced by polarization singularities.

Optical forces in the near fields have important applications in on-chip optical manipulations of small particles and molecules. Here, we report a study of optical force and torque on small particles induced by the optical polarization singularities of a gold cylinder. We show that the scattering of the cylinder generates both electric and magnetic C lines (i.e., lines of polarization singularities) in the near fields. The intrinsic spin density of the C lines can induce complex optical torque on a dielectric/magnetic particle, and the near-field evolutions of the C lines are accompanied by a gradient force on the particle. The force and torque manifest dramatic spatial variations, providing rich degrees of freedom for near-field optical manipulations. The study, for the first time to our knowledge, uncovers the effect of optical polarization singularities on light-induced force and torque on small particles. The results contribute to the understanding of chiral light-matter interactions and can find applications in on-chip optical manipulations and optical sensing.

Defect-assisted, spray-printed colloidal quantum dot microlasers for biosensing.

This study successfully implements spectrally distinguishable CdSe-ZnS core-shell colloidal quantum dot (CQD) microlasers by a simple, efficient spray printing technique and demonstrates its potential in biosensing. We have systematically characterized the optical properties of printed microring lasers with diameters less than 60 µm. The smallest structure that can be excited has a diameter as small as 30 µm, which is much smaller than the counterparts prepared by piezoelectric ink-jet printing. The detection sensitivity of 4.54 nm/min/refractive index unit is verified in glucose sensing using a printed CQD microlaser. Biosensing of diverse glucose and bovine serum albumin solutions using printed microlasers with the assistance of defects demonstrates a new, to the best of our knowledge, prototype for the development of high-performance, low-cost on-chip microcavity sensors.

Organocatalytic Asymmetric Construction of Tetrasubstituted Carbon Stereocenters Bearing Three Heteroatoms via Intramolecular Cyclization of Vinylidene ortho-Quinone Methide with Imidates.

We report herein an organocatalytic asymmetric protocol for the construction of tetrasubstituted carbon stereocenters bearing three heteroatoms. The reaction proceeded via the enantioselective intramolecular cyclization reaction of vinylidene ortho-quinone methide (VQM) with imidates to form pentacyclic heterocycles. The formed tetrasubstituted carbon center was stable under a high temperature and the conditions for further transformations.

Dynamic reprogramming of H3K9me3 at hominoid-specific retrotransposons during human preimplantation development.

Reprogramming of H3K9me3-dependent heterochromatin is required for early development. How H3K9me3 is involved in early human development remains, however, largely unclear. Here, we resolve the temporal landscape of H3K9me3 during human preimplantation development and its regulation for diverse hominoid-specific retrotransposons. At the 8-cell stage, H3K9me3 reprogramming at hominoid-specific retrotransposons termed SINE-VNTR-Alu (SVA) facilitates interaction between certain promoters and SVA-derived enhancers, promoting the zygotic genome activation. In trophectoderm, de novo H3K9me3 domains prevent pluripotent transcription factors from binding to hominoid-specific retrotransposons-derived regulatory elements for inner cell mass (ICM)-specific genes. H3K9me3 re-establishment at SVA elements in the ICM is associated with higher transcription of DNA repair genes, when compared with naive human pluripotent stem cells. Our data demonstrate that species-specific reorganization of H3K9me3-dependent heterochromatin at hominoid-specific retrotransposons plays important roles during early human development, shedding light on how the epigenetic regulation for early development has evolved in mammals.

Atroposelective Construction of Nine-Membered Carbonate-Bridged Biaryls.

We herein demonstrated an efficient method for the atroposelective construction of nine-membered carbonate-bridged biaryls through vinylidene ortho-quinone methide (VQM) intermediates. Diverse products with desirable pharmacological features were synthesized in satisfying yields and good to excellent enantioselectivities. In subsequent bioassays, several agents showed considerable antiproliferative activity via the mitochondrial-related apoptosis mechanism. Further transformations produced more structural diversity and may inspire new ideas for developing functional molecules.

Organocatalytic Asymmetric Dearomatizing Hetero-Diels-Alder Reaction of Nonactivated Arenes.

Nonactivated arenes, such as benzene derivatives, are chemically inert due to their intrinsic aromaticity and low polarity. The catalytic asymmetric dearomatization (CADA, coined by You and co-workers) of the nonactivated arenes represents a formidable challenge. We herein demonstrated an organocatalytic asymmetric dearomatizing hetero-Diels-Alder reaction of benzene derivatives. The tunable regioselectivity of this strategy allowed delivery of a diversity of stereochemically complex polycyclic compounds and oxahelicenes with excellent stereoselectivity. The high complexity and three-dimensionality of the products are crucial for their potential applications in materials science and drug discovery. Mechanistic studies suggested that this reaction proceeds through a chiral tetra-substituted vinylidene ortho-quinone methide (VQM) intermediate, which is extremely active to overcome the loss of aromaticity of benzene derivatives with concomitant chirality transfer.

Change in knee cartilage components in stroke patients with genu recurvatum analysed by zero TE MR imaging.

Genu recurvatum in stroke patients with hemiplegia causes readily cumulative damage and degenerative changes in the knee cartilage. It is important to detect early cartilage lesions for appropriate treatment and rehabilitation. The purpose of this cross-sectional study was to provide a theoretical basis for the early rehabilitation of hemiplegia patients. We used a zero TE double-echo imaging sequence to analyse the water content in knee joint cartilage at 12 different sites of 39 stroke patients with genu recurvatum and 9 healthy volunteers using a metric similar to the porosity index. When comparing the hemiplegic limb vs. the nonhemiplegic limb in patients, the ratios of the deep/shallow free water content of the femur cartilages at the anterior horn (1.16 vs. 1.06) and posterior horn (1.13 vs. 1.25) of the lateral meniscus were significantly different. Genu recurvatum in stroke patients with hemiplegia can cause changes in the moisture content of knee cartilage, and the changes in knee cartilage are more obvious as the genu recurvatum increases. The "healthy limb" can no longer be considered truly healthy and should be considered simultaneously with the affected limb in the development of a rehabilitation treatment plan.

Organocatalytic cascade reactions for multi-functionalized chiral cyclic ethers through vinylidene ortho-quinone methides.

An organocatalytic approach to installing various alcohols into the carbonyl of α,ß-unsaturated ketones mediated by VQM intermediates was achieved, followed by dearomatization to provide the stereo-defined cyclic ethers via a cascade process. Along with the transformations, this strategy affords efficient access to the underexplored chiral cyclic ether chemospace.

Olig3 regulates early cerebellar development.

The mature cerebellum controls motor skill precision and participates in other sophisticated brain functions that include learning, cognition, and speech. Different types of GABAergic and glutamatergic cerebellar neurons originate in temporal order from two progenitor niches, the ventricular zone and rhombic lip, which express the transcription factors Ptf1a and Atoh1, respectively. However, the molecular machinery required to specify the distinct neuronal types emanating from these progenitor zones is still unclear. Here, we uncover the transcription factor Olig3 as a major determinant in generating the earliest neuronal derivatives emanating from both progenitor zones in mice. In the rhombic lip, Olig3 regulates progenitor cell proliferation. In the ventricular zone, Olig3 safeguards Purkinje cell specification by curtailing the expression of Pax2, a transcription factor that suppresses the Purkinje cell differentiation program. Our work thus defines Olig3 as a key factor in early cerebellar development.

The SNAG Domain of Insm1 Regulates Pancreatic Endocrine Cell Differentiation and Represses ß- to δ-Cell Transdifferentiation.

The allocation and specification of pancreatic endocrine lineages are tightly regulated by transcription factors. Disturbances in differentiation of these lineages contribute to the development of various metabolic diseases, including diabetes. The insulinoma-associated protein 1 (Insm1), which encodes a protein containing one SNAG domain and five zinc fingers, plays essential roles in pancreatic endocrine cell differentiation and in mature ß-cell function. In the current study, we compared the differentiation of pancreatic endocrine cells between Insm1 null and Insm1 SNAG domain mutants (Insm1delSNAG) to explore the specific function of the SNAG domain of Insm1. We show that the δ-cell number is increased in Insm1delSNAG but not in Insm1 null mutants as compared with the control mice. We also show a less severe reduction of the ß-cell number in Insm1delSNAG as that in Insm1 null mutants. In addition, similar deficits are observed in α-, PP, and ε-cells in Insm1delSNAG and Insm1 null mutants. We further identified that the increased δ-cell number is due to ß- to δ-cell transdifferentiation. Mechanistically, the SNAG domain of Insm1 interacts with Lsd1, the demethylase of H3K4me1/2. Mutation in the SNAG domain of Insm1 results in impaired recruitment of Lsd1 and increased H3K4me1/2 levels at hematopoietically expressed homeobox (Hhex) loci that are bound by Insm1, thereby promoting the transcriptional activity of the δ-cell-specific gene Hhex Our study has identified a novel function of the SNAG domain of Insm1 in the regulation of pancreatic endocrine cell differentiation, particularly in the repression of ß- to δ-cell transdifferentiation.

Chiral Naphthyl-C2-Indole as Scaffold for Phosphine Organocatalysis: Application in Asymmetric Formal [4 + 2] Cycloaddition Reactions.

The applications of a newly designed chiral naphthyl-C2-indole bifunctional phosphine organocatalyst in stereoselective formal [4 + 2] cycloaddition reactions were reported. The chiral naphthyl-C2-indole skeleton was introduced to bifunctional phosphine organocatalysis for the first time, and excellent stereocontrol was achieved in two types of formal [4 + 2] cycloaddition reactions. With the optimal catalyst, a series of chiral spirooxindole and hydrodibenzofuran architectures were produced in moderate to good yields with excellent stereoselectivities (up to >99% ee, >20:1 dr).

N-Iodosuccinimide-Mediated Dimerization of 2-Alkynylnaphthols: A Highly Diastereoselective Construction of Bridged Polycyclic Compounds via Vinylidene ortho-Quinone Methide Intermediate.

An unprecedented highly diastereoselective dimerization of 2-alkynylnaphthols is presented to furnish bridged polycyclic compounds containing a bicyclo[3.2.1]octane moiety with good to excellent yields. The reaction proceeded under mild conditions using N-iodosuccinimide as a promoter, simultaneously constructing one new C-O bond and two new C-C bonds. A tetra-substituted vinylidene ortho-quinone methide intermediate was likely involved, and the steric hindrance of substituents played a critical role in this transformation.