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.

Near-Field Spin Chern Number Quantized by Real-Space Topology of Optical Structures.

The Chern number has been widely used to describe the topological properties of periodic structures in momentum space. Here, we introduce a real-space spin Chern number for the optical near fields of finite-sized structures. This new spin Chern number is intrinsically quantized and equal to the structure's Euler characteristic. The relationship is robust against continuous deformation of the structure's geometry and is irrelevant to the specific material constituents or external excitation. Our Letter enriches topological physics by extending the Chern number to real space, opening exciting possibilities for exploring the real-space topological properties of light.

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.

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.

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.

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.

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.

Insm1 cooperates with Neurod1 and Foxa2 to maintain mature pancreatic ß-cell function.

Key transcription factors control the gene expression program in mature pancreatic ß-cells, but their integration into regulatory networks is little understood. Here, we show that Insm1, Neurod1 and Foxa2 directly interact and together bind regulatory sequences in the genome of mature pancreatic ß-cells. We used Insm1 ablation in mature ß-cells in mice and found pronounced deficits in insulin secretion and gene expression. Insm1-dependent genes identified previously in developing ß-cells markedly differ from the ones identified in the adult. In particular, adult mutant ß-cells resemble immature ß-cells of newborn mice in gene expression and functional properties. We defined Insm1, Neurod1 and Foxa2 binding sites associated with genes deregulated in Insm1 mutant ß-cells. Remarkably, combinatorial binding of Insm1, Neurod1 and Foxa2 but not binding of Insm1 alone explained a significant fraction of gene expression changes. Human genomic sequences corresponding to the murine sites occupied by Insm1/Neurod1/Foxa2 were enriched in single nucleotide polymorphisms associated with glycolytic traits. Thus, our data explain part of the mechanisms by which ß-cells maintain maturity: Combinatorial Insm1/Neurod1/Foxa2 binding identifies regulatory sequences that maintain the mature gene expression program in ß-cells, and disruption of this network results in functional failure.

Enantioselective Control of Both Helical and Axial Stereogenic Elements though an Organocatalytic Approach.

A highly diastereo- and enantio-selective method for the asymmetric synthesis of molecules containing helicenes and stereogenic axes was developed based on organocatalysis. Various compounds bearing both helical and axial stereogenic elements were obtained in excellent enantioselectivities. The mechanism study revealed that the reaction proceeded through two stages: 1) The first cyclization produces a reaction intermediate containing a stereogenic axis. 2) The dynamic kinetic resolution of helix reaction intermediate following with cyclization generates a helix and another stereogenic axis.

Enantioselective Construction of Vicinal Diaxial Styrenes and Multiaxis System via Organocatalysis.

A highly diastereo- and enantioselective methodology for the asymmetric synthesis of vicinal diaxial styrenes and multiaxis system was achieved by organocatalysis. Various vicinal diaxial styrenes and multiaxis systems were obtained in excellent enantioselective manners. The mechanism studies revealed that a new tetra-substituted vinylidene ortho-quinone methide (VQM) intermediate was likely involved and accounted for the excellent enantioselectivity.

Organocatalytic Enantioselective Construction of Axially Chiral Sulfone-Containing Styrenes.

We describe herein an organocatalytic enantioselective approach for the construction of axially chiral sulfone-containing styrenes. Various axially chiral sulfone-containing styrene compounds were prepared with excellent enantioselectivities (up to >99% ee) and almost complete E/ Z selectivities (>99% E/ Z). Furthermore, the axially chiral sulfone-containing styrenes could be easily converted into phosphonic acid and S/P ligands, which could be potentially used as organocatalysts or ligands in asymmetric catalysis.

Enantioselective Synthesis of anti-syn-Trihalides and anti-syn-anti-Tetrahalides via Asymmetric ß-Elimination.

Structural motifs containing contiguous halide-bearing stereocenters are common in natural products as well as bioactive molecules. A few successful examples have been reported in the area of asymmetric vicinal dihalogenation of alkenes for accessing dihalogenated products; in this report, an alternative generation method of contiguous halide-bearing stereocenters α,ß,γ,δ relative to carbonyl group in excellent enantioselectivity is proposed by utilizing a Song's oligoEG catalyst-catalyzed asymmetric ß-elimination. According to this methodology, a wide range of anti-syn-trihalides and anti-syn-anti-tetrahalides with high levels of enantioselectivity were synthesized. The synthetic utility of the contiguous halide-bearing stereocenters was demonstrated by several transformations. The results of high-resolution mass spectrometry indicated that the favorable interaction between catalyst and one of the enantiomers of racemic contiguously multihalogenated ketone contributed to the original enantioselectivity of dehydrohalogenation. A deuterium kinetic isotope effect experiment revealed that this ß-elimination reaction proceeds by the E2 mechanism. This strategy opens a new pathway for the asymmetric synthesis of contiguous halide-bearing stereocenters of great complexity.

Organocatalytic Intramolecular [4+2] Cycloaddition between In Situ Generated Vinylidene ortho-Quinone Methides and Benzofurans.

Described herein is the enantioselective construction of oxygen-containing [5-6-5] tricyclic heterocycles by an organocatalyzed asymmetric [4+2] cycloaddition of vinylidene ortho-quinone methides and benzofurans. According to this methodology, a series of oxygen-containing [5-6-5] tricyclic heterocycles with various functional groups were synthesized in excellent enantio- and diastereoselectivities (>99 % ee, >20:1 d.r.). Furthermore, the deuterium-labeling experiments and high-resolution mass spectroscopy demonstrated that a vinylidene ortho-quinone methide intermediate was involved and possibly resulted from a prototropic rearrangement of 2-ethynylphenol. Remarkably, a catalyst loading as low as 0.1 mol %, and a gram-scale synthesis were achieved for this transformation.

Insm1 controls the differentiation of pulmonary neuroendocrine cells by repressing Hes1.

Epithelial progenitor cells of the lung generate all cell types of the mature airway epithelium, among them the neuroendocrine cells. The balance between formation of pulmonary neuroendocrine and non-neuroendocrine cells is controlled by Notch signaling. The Notch target gene Hes1 is expressed by non-neuroendocrine and absent in neuroendocrine cells. The transcription factor Ascl1 is expressed in a complementary pattern and provides key regulatory information that specifies the neuroendocrine cell fate. The molecular events that occur after the induction of the neuroendocrine differentiation program have received little attention. Here we show that Insm1 is expressed in pulmonary neuroendocrine cells, and that Insm1 expression is not initiated in the lung of Ascl1 mutant mice. We use mouse genetics to show that pulmonary neuroendocrine cells depend on Insm1 for their differentiation. Mutation of Insm1 blocks terminal differentiation, upregulates Hes1 protein in neuroendocrine cells and interferes with maintenance of Ascl1 expression. We show that Insm1 binds to the Hes1 promoter and represses Hes1, and we propose that the Insm1-dependent Hes1 repression is required for neuroendocrine development. Our work demonstrates that Insm1 is a key factor regulating differentiation of pulmonary neuroendocrine cells.

Insm1 controls development of pituitary endocrine cells and requires a SNAG domain for function and for recruitment of histone-modifying factors.

The Insm1 gene encodes a zinc finger factor expressed in many endocrine organs. We show here that Insm1 is required for differentiation of all endocrine cells in the pituitary. Thus, in Insm1 mutant mice, hormones characteristic of the different pituitary cell types (thyroid-stimulating hormone, follicle-stimulating hormone, melanocyte-stimulating hormone, adrenocorticotrope hormone, growth hormone and prolactin) are absent or produced at markedly reduced levels. This differentiation deficit is accompanied by upregulated expression of components of the Notch signaling pathway, and by prolonged expression of progenitor markers, such as Sox2. Furthermore, skeletal muscle-specific genes are ectopically expressed in endocrine cells, indicating that Insm1 participates in the repression of an inappropriate gene expression program. Because Insm1 is also essential for differentiation of endocrine cells in the pancreas, intestine and adrenal gland, it is emerging as a transcription factor that acts in a pan-endocrine manner. The Insm1 factor contains a SNAG domain at its N-terminus, and we show here that the SNAG domain recruits histone-modifying factors (Kdm1a, Hdac1/2 and Rcor1-3) and other proteins implicated in transcriptional regulation (Hmg20a/b and Gse1). Deletion of sequences encoding the SNAG domain in mice disrupted differentiation of pituitary endocrine cells, and resulted in an upregulated expression of components of the Notch signaling pathway and ectopic expression of skeletal muscle-specific genes. Our work demonstrates that Insm1 acts in the epigenetic and transcriptional network that controls differentiation of endocrine cells in the anterior pituitary gland, and that it requires the SNAG domain to exert this function in vivo.

Land use and river-lake connectivity: Biodiversity determinants of lake ecosystems.

Lake ecosystems confront escalating challenges to their stability and resilience, most intuitively leading to biodiversity loss, necessitating effective preservation strategies to safeguard aquatic environments. However, the complexity of ecological processes governing lake biodiversity under multi-stressor interactions remains an ongoing concern, primarily due to insufficient long-term bioindicator data, particularly concerning macroinvertebrate biodiversity. Here we utilize a unique, continuous, and in situ biomonitoring dataset spanning from 2011 to 2019 to investigate the spatio-temporal variation of macroinvertebrate communities. We assess the impact of four crucial environmental parameters on Lake Dongting and Lake Taihu, i.e., water quality, hydrology, climate change, and land use. These two systems are representative of lakes with Yangtze-connected and disconnected subtropical floodplains in China. We find an alarming trend of declining taxonomic and functional diversities among macroinvertebrate communities despite improvements in water quality. Primary contributing factors to this decline include persistent anthropogenic pressures, particularly alterations in human land use around the lakes, including intensified nutrient loads and reduced habitat heterogeneity. Notably, river-lake connectivity is pivotal in shaping differential responses to multiple stressors. Our results highlight a strong correlation between biodiversity alterations and land use within a 2-5 km radius and 0.05-2.5 km from the shorelines of Lakes Dongting and Taihu, respectively. These findings highlight the importance of implementing land buffer zones with specific spatial scales to enhance taxonomic and functional diversity, securing essential ecosystem services and enhancing the resilience of crucial lake 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.

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.

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.