A male germ-cell-specific ribosome controls male fertility.

Ribosomes are highly sophisticated translation machines that have been demonstrated to be heterogeneous in the regulation of protein synthesis1,2. Male germ cell development involves complex translational regulation during sperm formation3. However, it remains unclear whether translation during sperm formation is performed by a specific ribosome. Here we report a ribosome with a specialized nascent polypeptide exit tunnel, RibosomeST, that is assembled with the male germ-cell-specific protein RPL39L, the paralogue of core ribosome (RibosomeCore) protein RPL39. Deletion of RibosomeST in mice causes defective sperm formation, resulting in substantially reduced fertility. Our comparison of single-particle cryo-electron microscopy structures of ribosomes from mouse kidneys and testes indicates that RibosomeST features a ribosomal polypeptide exit tunnel of distinct size and charge states compared with RibosomeCore. RibosomeST predominantly cotranslationally regulates the folding of a subset of male germ-cell-specific proteins that are essential for the formation of sperm. Moreover, we found that specialized functions of RibosomeST were not replaceable by RibosomeCore. Taken together, identification of this sperm-specific ribosome should greatly expand our understanding of ribosome function and tissue-specific regulation of protein expression pattern in mammals.

Compact RNA editors with natural miniature Cas13j nucleases.

Clustered regularly interspaced short palindromic repeats-Cas13 effectors are used for RNA editing but the adeno-associated virus (AAV) packaging limitations because of their big sizes hinder their therapeutic application. Here we report the identification of the Cas13j family, with LepCas13j (529 aa) and ChiCas13j (424 aa) being the smallest and most highly efficient variants for RNA interference. The miniaturized Cas13j proteins enable the development of compact RNA base editors. Chi-RESCUE-S, by fusing dChiCas13j with hADAR2dd, demonstrates high efficiency and specificity in A-to-G and C-to-U conversions. Importantly, this system is compatible with single-AAV packaging without the need for protein sequence truncation. It successfully corrected pathogenic mutations, such as APOC3D65N and SCN9AR896Q, to the wild-type forms. In addition, we developed an optimized system, Chi-RESCUE-S-mini3, which pioneered efficient in vivo C-to-U RNA editing of PCSK9 in mice through single-AAV delivery, resulting in reduced total cholesterol levels. These results highlight the potential of Cas13j to treat human diseases.

Rationally Tailoring Chiral Molecules to Minimize Interfacial Energy Loss Enables Efficient and Stable Perovskite Solar Cells Using Vacuum Flash Technology.

Facing the defects and energy barrier at the interface of perovskite solar cells, we propose a chiral molecule engineering strategy to simultaneously heal interfacial defects and regulate interfacial energy band alignment. S-ibuprofen (S-IBU), R-ibuprofen (R-IBU), and racemic ibuprofen (rac-IBU) are used to post-treat perovskite films. rac-IBU molecules possess the strongest anchoring on the surface of perovskites among all chiral molecules, translating into the best defect passivation effect. The hydrophobic isobutyl group and benzene ring could increase the film moisture resistance ability. Due to reduced interfacial defects and interfacial energy barrier, rac-IBU enables efficient devices with a maximum efficiency exceeding 24% based on vacuum flash technology without antisolvents. The encapsulated rac-IBU-modified device could maintain 90% of its initial performance after 1040 h of continuous maximum power point tracking. This work provides a feasible route to minimize interfacial nonradiative recombination losses by controlling spatial conformation via rational chiral molecule engineering.

Molecular Synergistic Passivation for Efficient Perovskite Solar Cells and Self-Powered Photodetectors.

The interface between the perovskite and electron-transporting material is often treated for defect passivation to improve the photovoltaic performance of devices. A facile 4-Acetamidobenzoic acid (containing an acetamido, a carboxyl, and a benzene ring)-based molecular synergistic passivation (MSP) strategy is developed here to engineer the SnOx /perovskite interface, in which dense SnOx are prepared using an E-beam evaporation technology while the perovskite is deposited with vacuum flash evaporation deposition method. MSP engineering can synergistically passivate defects at the SnOx /perovskite interface by coordinating with Sn4+ and Pb2+ with functional group CO in the acetamido and carboxyl. The optimized solar cell devices can achieve the highest efficiency of 22.51% based on E-Beam deposited SnOx and 23.29% based on solution-processed SnO2 , respectively, accompanied by excellent stability exceeding 3000 h. Further, the self-powered photodetectors exhibit a remarkably low dark current of 5.22 × 10-9  A cm-2 , a response of 0.53 A W-1 at zero bias, a detection limit of 1.3 × 1013  Jones, and a linear dynamic range up to 80.4 dB. This work proposes a molecular synergistic passivation strategy to enhance the efficiency and responsivity of solar cells and self-powered photodetectors.

Ameliorative effect of Luffa cylindrica fruits on Caenorhabditis elegans and cellular models of Alzheimer's disease-related pathology via autophagy induction.

BACKGROUND: Alzheimer's disease (AD) is a prevalent neurodegenerative disorder without an effective cure. Natural products, while showing promise as potential therapeutics for AD, remain underexplored. AIMS: This study was conducted with the goal of identifying potential anti-AD candidates from natural sources using Caenorhabditis elegans (C. elegans) AD-like models and exploring their mechanisms of action. MATERIALS & METHODS: Our laboratory's in-house herbal extract library was utilized to screen for potential anti-AD candidates using the C. elegans AD-like model CL4176. The neuroprotective effects of the candidates were evaluated in multiple C. elegans AD-like models, specifically targeting Aß- and Tau-induced pathology. In vitro validation was conducted using PC-12 cells. To investigate the role of autophagy in mediating the anti-AD effects of the candidates, RNAi bacteria and autophagy inhibitors were employed. RESULTS: The ethanol extract of air-dried fruits of Luffa cylindrica (LCE), a medicine-food homology species, was found to inhibit Aß- and Tau-induced pathology (paralysis, ROS production, neurotoxicity, and Aß and pTau deposition) in C. elegans AD-like models. LCE was non-toxic and enhanced C. elegans' health. It was shown that LCE activates autophagy and its anti-AD efficacy is weakened with the RNAi knockdown of autophagy-related genes. Additionally, LCE induced mTOR-mediated autophagy, reduced the expression of AD-associated proteins, and decreased cell death in PC-12 cells, which was reversed by autophagy inhibitors (bafilomycin A1 and 3-methyladenine). DISCUSSION: LCE, identified from our natural product library, emerged as a valuable autophagy enhancer that effectively protects against neurodegeneration in multiple AD-like models. RNAi knockdown of autophagy-related genes and cotreatment with autophagy inhibitors weakened its anti-AD efficacy, implying a critical role of autophagy in mediating the neuroprotective effects of LCE. CONCLUSION: Our findings highlight the potential of LCE as a functional food or drug for targeting AD pathology and promoting human health.

Automatic Image Segmentation and Grading Diagnosis of Sacroiliitis Associated with AS Using a Deep Convolutional Neural Network on CT Images.

Ankylosing spondylitis (AS) is a chronic inflammatory disease that causes inflammatory low back pain and may even limit activity. The grading diagnosis of sacroiliitis on imaging plays a central role in diagnosing AS. However, the grading diagnosis of sacroiliitis on computed tomography (CT) images is viewer-dependent and may vary between radiologists and medical institutions. In this study, we aimed to develop a fully automatic method to segment sacroiliac joint (SIJ) and further grading diagnose sacroiliitis associated with AS on CT. We studied 435 CT examinations from patients with AS and control at two hospitals. No-new-UNet (nnU-Net) was used to segment the SIJ, and a 3D convolutional neural network (CNN) was used to grade sacroiliitis with a three-class method, using the grading results of three veteran musculoskeletal radiologists as the ground truth. We defined grades 0-I as class 0, grade II as class 1, and grades III-IV as class 2 according to modified New York criteria. nnU-Net segmentation of SIJ achieved Dice, Jaccard, and relative volume difference (RVD) coefficients of 0.915, 0.851, and 0.040 with the validation set, respectively, and 0.889, 0.812, and 0.098 with the test set, respectively. The areas under the curves (AUCs) of classes 0, 1, and 2 using the 3D CNN were 0.91, 0.80, and 0.96 with the validation set, respectively, and 0.94, 0.82, and 0.93 with the test set, respectively. 3D CNN was superior to the junior and senior radiologists in the grading of class 1 for the validation set and inferior to expert for the test set (P < 0.05). The fully automatic method constructed in this study based on a convolutional neural network could be used for SIJ segmentation and then accurately grading and diagnosis of sacroiliitis associated with AS on CT images, especially for class 0 and class 2. The method for class 1 was less effective but still more accurate than that of the senior radiologist.

Discovery of 4-(3-aminopyrrolidinyl)-3-aryl-5-(benzimidazol-2-yl)-pyridines as potent and selective SST5 agonists for the treatment of congenital hyperinsulinism.

SST5 receptor activation potently inhibits insulin secretion from pancreatic ß-cells, and an orally available nonpeptide selective SST5 agonist may be used to effectively manage the blood glucose levels of congenital HI patients to avoid severe hypoglycemia. Our medicinal chemistry efforts have led to the discovery of 4-(3-aminopyrrolidinyl)-3-aryl-5-(benzimidazol-2-yl)-pyridine analogs as potent SST5 agonists. This class of molecules exhibits excellent human SST5 potency and selectivity against SST1, SST2, SST3 and SST4 receptors. Leading compound 3-{4-[(3S)-3-aminopyrrolidin-1-yl]-5-(4-methyl-1H-1,3-benzodiazol-2-yl)pyridin-3-yl-5-fluorobenzonitrile (28, CRN02481) showed limited off-target activity and good pharmacokinetic profiles in both male Sprague Dawley rats and Beagle dogs to advance into further preclinical evaluations.

Human X chromosome exome sequencing identifies BCORL1 as contributor to spermatogenesis.

BACKGROUND: Infertility affects approximately 15% of couples worldwide with male infertility being responsible for approximately 50% of cases. Although accumulating evidence demonstrates the critical role of the X chromosome in spermatogenesis during the last few decades, the expression patterns and potential impact of the X chromosome, together with X linked genes, on male infertility are less well understood. METHODS: We performed X chromosome exome sequencing followed by a two-stage independent population validation in 1333 non-obstructive azoospermia cases and 1141 healthy controls to identify variant classes with high likelihood of pathogenicity. To explore the functions of these candidate genes in spermatogenesis, we first knocked down these candidate genes individually in mouse spermatogonial stem cells (SSCs) using short interfering RNA oligonucleotides and then generated candidate genes knockout mice by CRISPR-Cas9 system. RESULTS: Four low-frequency variants were identified in four genes (BCORL1, MAP7D3, ARMCX4 and H2BFWT) associated with male infertility. Functional studies of the mouse SSCs revealed that knocking down Bcorl1 or Mtap7d3 could inhibit SSCs self-renewal and knocking down Armcx4 could repress SSCs differentiation in vitro. Using CRISPR-Cas9 system, Bcorl1 and Mtap7d3 knockout mice were generated. Excitingly, Bcorl1 knockout mice were infertile with impaired spermatogenesis. Moreover, Bcorl1 knockout mice exhibited impaired sperm motility and sperm cells displayed abnormal mitochondrial structure. CONCLUSION: Our data indicate that the X-linked genes are associated with male infertility and involved in regulating SSCs, which provides a new insight into the role of X-linked genes in spermatogenesis.

Mebendazole-Induced Blood-Testis Barrier Injury in Mice Testes by Disrupting Microtubules in Addition to Triggering Programmed Cell Death.

Mebendazole (MBZ) is a synthetic benzimidazole known for its antiparasitic properties. In recent years, growing evidence showed that MBZ was also used as an anti-tumor agent. However, whether (and to what extent) this drug treatment affected the male reproductive system was not well-understood. In this study, male C57BL/6 mice were injected with 40 mg/kg/day of MBZ. The treatment was for 3 and 7 days. Our results showed that the injected mice exhibited an abnormal spermatogenic phase with a significant decrease in sperm. We further detected microtubule disruption and transient functional destruction of the blood-testes barrier (BTB) in the MBZ-injected mice testes (BTB). Our data confirmed that MBZ suppressed the expression of the BTB junction-associated proteins and disrupted the Sertoli cells' function in vivo. Moreover, MBZ-treated mice demonstrated an aberrant caspase-3 signalling pathway, which resulted in the apoptosis of the germ cells. Here, we present our data, indicating that MBZ impairs BTB by reducing the expression of the microtubules' and BTB junction-associated proteins. The last leads to activating the caspase-3 pathway, which triggers extensive germ cell apoptosis.

Discovery of substituted 3H-pyrido[2,3-d]pyrimidin-4-ones as potent, biased, and orally bioavailable sst2 agonist.

The discovery of a novel 3H-pyrido[2,3-d]pyrimidin-4-one series as potent and biased sst2 agonists is described. This class of molecules exhibits excellent sst2 potency and selectivity against sst1, sst3, and sst5 receptors, and they are significantly more potent at inhibiting cAMP production than inducing internalization. The orally bioavailable 6-(3-chloro-5-methylphenyl)-3-(3-fluoro-5-hydroxyphenyl)-5-({methyl[(2S)-pyrrolidin-2-ylmethyl]amino}methyl)-3H,4H-pyrido[2,3-d]pyrimidin-4-one (36) also suppresses GH secretion in GHRH-challenged rats in a dose-dependent manner.

Discovery of nonpeptide 3,4-dihydroquinazoline-4-carboxamides as potent and selective sst2 agonists.

Nonpeptide sst2 agonists can provide a new treatment option for patients with acromegaly, carcinoid tumors, and neuroendocrine tumors. Our medicinal chemistry efforts have led to the discovery of novel 3,4-dihydroquinazoline-4-carboxamides as sst2 agonists. This class of molecules exhibits excellent human sst2 potency and selectivity against sst1, sst3, sst4 and sst5 receptors. Leading compound 3-(3-chloro-5-methylphenyl)-6-(3-fluoro-2-hydroxyphenyl)-N,7-dimethyl-N-{[(2S)-pyrrolidin-2-yl]methyl}-3,4-dihydroquinazoline-4-carboxamide (28) showed no inhibition of major CYP450 enzymes (2C9, 2C19, 2D6 and 3A4) and weak inhibition of the hERG channel.

Identification of a GntR family regulator BusRTha and its regulatory mechanism in the glycine betaine ABC transport system of Tetragenococcus halophilus.

Glycine betaine is one of the most effective compatible solutes of the halophilic lactic acid bacterium Tetragenococcus halophilus, the transportation of which is essential for its survival under salinity stress condition. In the current study, we attempted to define a glycine betaine ABC transporter system of T. halophilus, busATha, which plays an important role in adapting to salinity condition. The expression of busATha enhanced the growth of the recombinant strain under high salinity. BusRTha, a transcription regulator that represses the expression of busATha, was characterized, and the repression was abrogated under high salinity. The binding of the regulator was demonstrated through electrophoretic mobility shift assays, and the binding sites were characterized as 5'-AAA(T/G)TGAC(C/A)(G/A)T(C/A)C-3'. This is the first studied transcription regulator of T. halophilus, and our findings provide insights into the molecular mechanism of halophilic life and tools for further application of halophiles as chassis in industrial biotechnology.

Mechanisms of Cr(VI) reduction by Bacillus sp. CRB-1, a novel Cr(VI)-reducing bacterium isolated from tannery activated sludge.

Cr(VI) reduction by microorganisms has been extensively reported, however, the mechanism of Cr(VI) reduction varies among different microorganisms. In this study, a Cr(VI)-reducing bacterium identified as Bacillus sp. was isolated from tannery activated sludge, strain CRB-1 was able to completely reduce 50 mg/L of Cr(VI) within 24 h under aerobic conditions and exhibited considerable Cr(VI) removal efficiency in the pH range from 7.0 to 9.0, temperature 24-42 °C. Cr(VI) reduction assays with resting cells, permeabilized cells, and subcellular fractions suggested that Cr(VI) reduction mainly occurred in the cytoplasm. According to qRT-PCR analysis, a chrA gene and a nitR2 gene were up-regulated under Cr(VI) stress. Heterologous expression of the chrA gene and the nitR2 gene indicated that ChrA was associated with Cr(VI) resistance, while NitR2 was responsible for Cr(VI) reduction. Furthermore, soluble end products were detected. On the basis of FTIR, it was speculated that the formation of soluble end products may be due to the complexation of EPS with Cr(III). Consequently, the Cr(VI)-reducing ability of strain CRB-1 and its chromate reductases enables CRB-1 a potential candidate for Cr(VI) bioremediation.

The physiological cold tolerance of warm-climate plants is correlated with their latitudinal range limit.

Plants are moving poleward and upward in response to climate warming. However, such movements lag behind the expanding warming front for many reasons, including the impediment of plant movement caused by unusual cold events. In this study, we measured the maximum photochemical efficiency of photosystem II (Fv/Fm) in 101 warm-climate angiosperm species to assess their cold tolerance at the end of a severe chilling period of 49 days in a southern subtropical region (Nanning) in China. We found that 36 of the 101 species suffered from chilling-induced physiological injury, with predawn Fv/Fm values of less than 0.7. There was a significant exponential relationship between the predawn Fv/Fm and northern latitudinal limit of a species; species with a lower latitudinal limit suffered more. Our results suggest that the range limits of warm-climate plants are potentially influenced by their physiological sensitivity to chilling temperatures and that their poleward movement might be impeded by extreme cold events. The quick measurement of Fv/Fm is useful for assessing the cold tolerance of plants, providing valuable information for modelling species range shifts under changing climate conditions and species selection for horticultural management and urban landscape design.

Wafer-scale fabrication of high-density nanoslit arrays for surface-enhanced Raman spectroscopy.

Surfaces with a periodic nanostructure and controllable feature size are sought after for optical applications, and the fabrication of such surfaces in large areas with high reproducibility, good stability and low deviation is very important. We present a strategy to fabricate large-area nanoslit arrays with controllable pitches and gaps. Au nanoslit arrays with gaps down to around 10 nm and a high gap density of 2.0 × 104 cm-1 have been fabricated, which can greatly enhance the near-field electromagnetic field to achieve localized surface plasmon resonance (LSPR). An averaged surface-enhanced Raman scattering analytical enhancement factor of 8.0 × 107 has been achieved on the substrate using a 633 nm laser source and the 'coupling effect' of LSPR of the nanoslits.

Vitamin D status and neuromyelitis optica spectrum disease: A systematic review and meta-analysis.

BACKGROUND AND OBJECTIVE: There's an increasing body of evidence on vitamin D deficiency and the risk of neuromyelitis optica spectrum disorder (NMOSD). The aim of this meta-analysis was to assess serum vitamin D levels in patients with NMOSD versus healthy controls. METHODS: We searched PubMed, EMBASE, Cochrane Library, Web of Science and CNKI for publications up to November 2022 and explored the relationship between NMOSD and serum vitamin D levels. The standardized mean differences (SMD) and 95% confidence intervals (CI) were calculated using a random-effects model. Subgroup analysis and sensitivity analysis were applied to explore the sources of heterogeneity. Begg's test, Egger's test, and Egger's funnel plot were adopted to evaluate publication bias. RESULTS: 6 studies (including 319 patients and 595 healthy controls) met the inclusion criteria and all compared vitamin D levels in patients with NMOSD versus healthy controls. Levels of serum vitamin D detected in NMOSD patients were significantly lower than those in healthy controls (SMD=-1.57, 95% CI=-2.27 ∼ -0.87, P<0.001, I2 = 94.6%). The results of the different sensitivity analysis remained statistically significant, which demonstrated the robustness of the meta-analysis. There was no significant publication bias in our meta-analysis (P>0.05). CONCLUSION: Patients with NMOSD showed significantly reduced vitamin D levels compared with healthy controls. Our findings highlighted the importance of measuring vitamin D levels in patients with NMOSD. Multi-center randomized controlled trials with large samples will further confirm whether the association is casual and modifiable.

Single-Cell Sequencing Combined with Transcriptome Sequencing Constructs a Predictive Model of Key Genes in Multiple Sclerosis and Explores Molecular Mechanisms Related to Cellular Communication.

Background: Multiple sclerosis (MS) causes chronic inflammation and demyelination of the central nervous system and comprises a class of neurodegenerative diseases in which interactions between multiple immune cell types mediate the involvement of MS development. However, the early diagnosis and treatment of MS remain challenging. Methods: Gene expression profiles of MS patients were obtained from the Gene Expression Omnibus (GEO) database. Single-cell and intercellular communication analyses were performed to identify candidate gene sets. Predictive models were constructed using LASSO regression. Relationships between genes and immune cells were analyzed by single sample gene set enrichment analysis (ssGSEA). The molecular mechanisms of key genes were explored using gene enrichment analysis. An miRNA network was constructed to search for target miRNAs related to key genes, and related transcription factors were searched by transcriptional regulation analysis. We utilized the GeneCard database to detect the correlations between disease-regulated genes and key genes. We verified the mRNA expression of 4 key genes by reverse transcription-quantitative PCR (RT‒qPCR). Results: Monocyte marker genes were selected as candidate gene sets. CD3D, IL2RG, MS4A6A, and NCF2 were found to be the key genes by LASSO regression. We constructed a prediction model with AUC values of 0.7569 and 0.719. The key genes were closely related to immune factors and immune cells. We explored the signaling pathways and molecular mechanisms involving the key genes by gene enrichment analysis. We obtained and visualized the miRNAs associated with the key genes using the miRcode database. We also predicted the transcription factors involved. We used validated key genes in MS patients, several of which were confirmed by RT‒qPCR. Conclusion: The prediction model constructed with the CD3D, IL2RG, MS4A6A, and NCF2 genes has good diagnostic efficacy and provides new ideas for the diagnosis and treatment of MS.

Neurometabolic and Brain Functional Alterations Associated with Cognitive Impairment in Patients with Myasthenia Gravis: A Combined 1H-MRS and fMRI Study.

Whether patients with myasthenia gravis (MG) exhibit cognitive impairment is controversial. Also the underlying mechanisms are unknown. We aimed to investigate alterations in cognitive function, neurometabolite levels, and brain function in patients with MG and to explore the associations between abnormal regional brain functional activity, neurometabolite concentrations in the MPFC and left thalamus, and cognitive activity in patients with MG. Neuropsychological tests, proton magnetic resonance spectroscopy, and resting-state functional magnetic resonance imaging were performed on 41 patients with MG and 45 race-, sex-, age-, and education-matched healthy controls (HCs). The results suggest that MG is accompanied by cognitive decline, as indicated by global cognitive function, visual-spatial function, language, memory, abnormalities in regional brain functional activity, and neurometabolite alterations (including GABA, NAA, and Cho) in the medial prefrontal cortex (MPFC) and left thalamus. Cognitive impairment in patients with MG may be related to abnormal regional brain functional activity and changes in neurometabolites, and regional brain functional activity may be modulated by specific neurometabolites.