The role of ThPOK in control of CD4/CD8 lineage commitment.

During alphabeta T cell development, cells diverge into alternate CD4 helper and CD8(+) cytotoxic T cell lineages. The precise correlation between a T cell's CD8 and CD4 choice and its TCR specificity to class I or class II MHC was noted more than 20 years ago, and establishing the underlying mechanism has remained a focus of intense study since then. This review deals with three formerly discrete topics that are gradually becoming interconnected: the role of TCR signaling in lineage commitment, the regulation of expression of the CD4 and CD8 genes, and transcriptional regulation of lineage commitment. It is widely accepted that TCR signaling exerts a decisive influence on lineage choice, although the underlying mechanism remains intensely debated. Current evidence suggests that both duration and intensity of TCR signaling may control lineage choice, as proposed by the kinetic signaling and quantitative instructive models, respectively. Alternate expression of the CD4 and CD8 genes is the most visible manifestation of lineage choice, and much progress has been made in defining the responsible cis elements and transcription factors. Finally, important clues to the molecular basis of lineage commitment have been provided by the recent identification of the transcription factor ThPOK as a key regulator of lineage choice. ThPOK is selectively expressed in class II-restricted cells at the CD4(+)8(lo) stage and is necessary and sufficient for development to the CD4 lineage. Given the central role of ThPOK in lineage commitment, understanding its upstream regulation and downstream gene targets is expected to reveal further important aspects of the molecular machinery underlying lineage commitment.

WNT signalling control by KDM5C during development affects cognition.

Although KDM5C is one of the most frequently mutated genes in X-linked intellectual disability1, the exact mechanisms that lead to cognitive impairment remain unknown. Here we use human patient-derived induced pluripotent stem cells and Kdm5c knockout mice to conduct cellular, transcriptomic, chromatin and behavioural studies. KDM5C is identified as a safeguard to ensure that neurodevelopment occurs at an appropriate timescale, the disruption of which leads to intellectual disability. Specifically, there is a developmental window during which KDM5C directly controls WNT output to regulate the timely transition of primary to intermediate progenitor cells and consequently neurogenesis. Treatment with WNT signalling modulators at specific times reveal that only a transient alteration of the canonical WNT signalling pathway is sufficient to rescue the transcriptomic and chromatin landscapes in patient-derived cells and to induce these changes in wild-type cells. Notably, WNT inhibition during this developmental period also rescues behavioural changes of Kdm5c knockout mice. Conversely, a single injection of WNT3A into the brains of wild-type embryonic mice cause anxiety and memory alterations. Our work identifies KDM5C as a crucial sentinel for neurodevelopment and sheds new light on KDM5C mutation-associated intellectual disability. The results also increase our general understanding of memory and anxiety formation, with the identification of WNT functioning in a transient nature to affect long-lasting cognitive function.

Uridine-derived ribose fuels glucose-restricted pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDA) is a lethal disease notoriously resistant to therapy1,2. This is mediated in part by a complex tumour microenvironment3, low vascularity4, and metabolic aberrations5,6. Although altered metabolism drives tumour progression, the spectrum of metabolites used as nutrients by PDA remains largely unknown. Here we identified uridine as a fuel for PDA in glucose-deprived conditions by assessing how more than 175 metabolites impacted metabolic activity in 21 pancreatic cell lines under nutrient restriction. Uridine utilization strongly correlated with the expression of uridine phosphorylase 1 (UPP1), which we demonstrate liberates uridine-derived ribose to fuel central carbon metabolism and thereby support redox balance, survival and proliferation in glucose-restricted PDA cells. In PDA, UPP1 is regulated by KRAS-MAPK signalling and is augmented by nutrient restriction. Consistently, tumours expressed high UPP1 compared with non-tumoural tissues, and UPP1 expression correlated with poor survival in cohorts of patients with PDA. Uridine is available in the tumour microenvironment, and we demonstrated that uridine-derived ribose is actively catabolized in tumours. Finally, UPP1 deletion restricted the ability of PDA cells to use uridine and blunted tumour growth in immunocompetent mouse models. Our data identify uridine utilization as an important compensatory metabolic process in nutrient-deprived PDA cells, suggesting a novel metabolic axis for PDA therapy.

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.

Noncanonical Wnt signaling maintains hematopoietic stem cells in the niche.

Wnt signaling is involved in self-renewal and maintenance of hematopoietic stem cells (HSCs); however, the particular role of noncanonical Wnt signaling in regulating HSCs in vivo is largely unknown. Here, we show Flamingo (Fmi) and Frizzled (Fz) 8, members of noncanonical Wnt signaling, both express in and functionally maintain quiescent long-term HSCs. Fmi regulates Fz8 distribution at the interface between HSCs and N-cadherin(+) osteoblasts (N-cad(+)OBs that enrich osteoprogenitors) in the niche. We further found that N-cad(+)OBs predominantly express noncanonical Wnt ligands and inhibitors of canonical Wnt signaling under homeostasis. Under stress, noncanonical Wnt signaling is attenuated and canonical Wnt signaling is enhanced in activation of HSCs. Mechanistically, noncanonical Wnt signaling mediated by Fz8 suppresses the Ca(2+)-NFAT- IFNγ pathway, directly or indirectly through the CDC42-CK1α complex and also antagonizes canonical Wnt signaling in HSCs. Taken together, our findings demonstrate that noncanonical Wnt signaling maintains quiescent long-term HSCs through Fmi and Fz8 interaction in the niche.

Tiki1 is required for head formation via Wnt cleavage-oxidation and inactivation.

Secreted Wnt morphogens are signaling molecules essential for embryogenesis, pathogenesis, and regeneration and require distinct modifications for secretion, gradient formation, and activity. Whether Wnt proteins can be posttranslationally inactivated during development and homeostasis is unknown. Here we identify, through functional cDNA screening, a transmembrane protein Tiki1 that is expressed specifically in the dorsal Spemann-Mangold Organizer and is required for anterior development during Xenopus embryogenesis. Tiki1 antagonizes Wnt function in embryos and human cells via a TIKI homology domain that is conserved from bacteria to mammals and acts likely as a protease to cleave eight amino-terminal residues of a Wnt protein, resulting in oxidized Wnt oligomers that exhibit normal secretion but minimized receptor-binding capability. Our findings identify a Wnt-specific protease that controls head formation, reveal a mechanism for morphogen inactivation through proteolysis-induced oxidation-oligomerization, and suggest a role of the Wnt amino terminus in evasion of oxidizing inactivation. TIKI proteins may represent potential therapeutic targets.

Tet3 CXXC domain and dioxygenase activity cooperatively regulate key genes for Xenopus eye and neural development.

Ten-Eleven Translocation (Tet) family of dioxygenases dynamically regulates DNA methylation and has been implicated in cell lineage differentiation and oncogenesis. Yet their functions and mechanisms of action in gene regulation and embryonic development are largely unknown. Here, we report that Xenopus Tet3 plays an essential role in early eye and neural development by directly regulating a set of key developmental genes. Tet3 is an active 5mC hydroxylase regulating the 5mC/5hmC status at target gene promoters. Biochemical and structural studies further demonstrate that the Tet3 CXXC domain is critical for specific Tet3 targeting. Finally, we show that the enzymatic activity and CXXC domain are both crucial for Tet3's biological function. Together, these findings define Tet3 as a transcription regulator and reveal a molecular mechanism by which the 5mC hydroxylase and DNA binding activities of Tet3 cooperate to control target gene expression and embryonic development.

Enhancer activation via TCP and HD-ZIP and repression by Dof transcription factors mediate giant cell-specific expression.

Proper cell-type identity relies on highly coordinated regulation of gene expression. Regulatory elements such as enhancers can produce cell type-specific expression patterns, but the mechanisms underlying specificity are not well understood. We previously identified an enhancer region capable of driving specific expression in giant cells, which are large, highly endoreduplicated cells in the Arabidopsis thaliana sepal epidermis. In this study, we use the giant cell enhancer as a model to understand the regulatory logic that promotes cell type-specific expression. Our dissection of the enhancer revealed that giant cell specificity is mediated primarily through the combination of two activators and one repressor. HD-ZIP and TCP transcription factors are involved in the activation of expression throughout the epidermis. High expression of HD-ZIP transcription factor genes in giant cells promoted higher expression driven by the enhancer in giant cells. Dof transcription factors repressed the activity of the enhancer such that only giant cells maintained enhancer activity. Thus, our data are consistent with a conceptual model whereby cell type-specific expression emerges from the combined activities of three transcription factor families activating and repressing expression in epidermal cells.

Targeted inhibition of Wnt signaling with a Clostridioides difficile toxin B fragment suppresses breast cancer tumor growth.

Wnt signaling pathways are transmitted via 10 homologous frizzled receptors (FZD1-10) in humans. Reagents broadly inhibiting Wnt signaling pathways reduce growth and metastasis of many tumors, but their therapeutic development has been hampered by the side effect. Inhibitors targeting specific Wnt-FZD pair(s) enriched in cancer cells may reduce side effect, but the therapeutic effect of narrow-spectrum Wnt-FZD inhibitors remains to be established in vivo. Here, we developed a fragment of C. difficile toxin B (TcdBFBD), which recognizes and inhibits a subclass of FZDs, FZD1/2/7, and examined whether targeting this FZD subgroup may offer therapeutic benefits for treating breast cancer models in mice. Utilizing 2 basal-like and 1 luminal-like breast cancer models, we found that TcdBFBD reduces tumor-initiating cells and attenuates growth of basal-like mammary tumor organoids and xenografted tumors, without damaging Wnt-sensitive tissues such as bones in vivo. Furthermore, FZD1/2/7-positive cells are enriched in chemotherapy-resistant cells in both basal-like and luminal mammary tumors treated with cisplatin, and TcdBFBD synergizes strongly with cisplatin in inhibiting both tumor types. These data demonstrate the therapeutic value of narrow-spectrum Wnt signaling inhibitor in treating breast cancers.

Metformin induction of heat shock factor 1 activation and the mitochondrial unfolded protein response alleviate cardiac remodeling in spontaneously hypertensive rats.

Heart failure and cardiac remodeling are both characterized by mitochondrial dysfunction. Healthy mitochondria are required for adequate contractile activity and appropriate regulation of cell survival. In the mammalian heart, enhancement of the mitochondrial unfolded protein response (UPRmt) is cardioprotective under pressure overload conditions. We explored the UPRmt and the underlying regulatory mechanism in terms of hypertension-induced cardiac remodeling and the cardioprotective effect of metformin. Male spontaneously hypertensive rats and angiotensin II-treated neonatal rat cardiomyocytes were used to induce cardiac hypertrophy. The results showed that hypertension induced the formation of aberrant mitochondria, characterized by a reduced mtDNA/nDNA ratio and swelling, as well as lower levels of mitochondrial complexes I to V and inhibition of the expression of one protein subunit of each of complexes I to IV. Such changes eventually enlarged cardiomyocytes and increased cardiac fibrosis. Metformin treatment increased the mtDNA/nDNA ratio and regulated the UPRmt, as indicated by increased expression of activating transcription factor 5, Lon protease 1, and heat shock protein 60, and decreased expression of C/EBP homologous protein. Thus, metformin improved mitochondrial ultrastructure and function in spontaneously hypertensive rats. In vitro analyses revealed that metformin reduced the high levels of angiotensin II-induced mitochondrial reactive oxygen species in such animals and stimulated nuclear translocation of heat shock factor 1 (HSF1). Moreover, HSF1 small-interfering RNA reduced the metformin-mediated improvements in mitochondrial morphology and the UPRmt by suppressing hypertrophic signals and cardiomyocyte apoptosis. These results suggest that HSF1/UPRmt signaling contributes to the beneficial effects of metformin. Metformin-mediated targeting of mitochondrial protein homeostasis and modulation of HSF1 levels have potential therapeutic implications in terms of cardiac remodeling.

Frizzled receptors facilitate Tiki inhibition of Wnt signaling at the cell surface.

The membrane-tethered protease Tiki antagonizes Wnt3a signaling by cleaving and inactivating Wnt3a in Wnt-producing cells. Tiki also functions in Wnt-receiving cells to antagonize Wnt signaling by an unknown mechanism. Here, we demonstrate that Tiki inhibition of Wnt signaling at the cell surface requires Frizzled (FZD) receptors. Tiki associates with the Wnt-FZD complex and cleaves the N-terminus of Wnt3a or Wnt5a, preventing the Wnt-FZD complex from recruiting and activating the coreceptor LRP6 or ROR1/2 without affecting Wnt-FZD complex stability. Intriguingly, we demonstrate that the N-terminus of Wnt3a is required for Wnt3a binding to LRP6 and activating ß-catenin signaling, while the N-terminus of Wnt5a is dispensable for recruiting and phosphorylating ROR1/2. Both Tiki enzymatic activity and its association with the Wnt-FZD complex contribute to its inhibitory function on Wnt5a. Our study uncovers the mechanism by which Tiki antagonizes Wnt signaling at the cell surface and reveals a negative role of FZDs in Wnt signaling by acting as Tiki cofactors. Our findings also reveal an unexpected role of the Wnt3a N-terminus in the engagement of the coreceptor LRP6.

Electron pairing in the pseudogap state revealed by shot noise in copper oxide junctions.

In the quest to understand high-temperature superconductivity in copper oxides, debate has been focused on the pseudogap-a partial energy gap that opens over portions of the Fermi surface in the 'normal' state above the bulk critical temperature1. The pseudogap has been attributed to precursor superconductivity, to the existence of preformed pairs and to competing orders such as charge-density waves1-4. A direct determination of the charge of carriers as a function of temperature and bias could help resolve among these alternatives. Here we report measurements of the shot noise of tunnelling current in high-quality La2-xSrxCuO4/La2CuO4/La2-xSrxCuO4 (LSCO/LCO/LSCO) heterostructures fabricated using atomic layer-by-layer molecular beam epitaxy at several doping levels. The data delineate three distinct regions in the bias voltage-temperature space. Well outside the superconducting gap region, the shot noise agrees quantitatively with independent tunnelling of individual charge carriers. Deep within the superconducting gap, shot noise is greatly enhanced, reminiscent of multiple Andreev reflections5-7. Above the critical temperature and extending to biases much larger than the superconducting gap, there is a broad region in which the noise substantially exceeds theoretical expectations for single-charge tunnelling, indicating pairing of charge carriers. These pairs are detectable deep into the pseudogap region of temperature and bias. The presence of these pairs constrains current models of the pseudogap and broken symmetry states, while phase fluctuations limit the domain of superconductivity.

Sulforaphane inhibits the migration and invasion of BPDE-induced lung adenocarcinoma cells by regulating NLRP12.

This study aims to explore the impact and underlying mechanism of sulforaphane (SFN) intervention on the migration and invasion of lung adenocarcinoma induced by 7, 8-dihydroxy-9, 10-epoxy-benzo (a) pyrene (BPDE). Human lung adenocarcinoma A549 cells were exposed to varying concentrations of BPDE (0.25, 0.50, and 1.00 µM) and subsequently treated with 5 µM SFN. Cell viability was determined using CCK8 assay, while migration and invasion were assessed using Transwell assays. Lentivirus transfection was employed to establish NLRP12 overexpressing A549 cells. ELISA was utilized to quantify IL-33, CXCL12, and CXCL13 levels in the supernatant, while quantitative real-time PCR (qRT-PCR) and Western Blot were used to analyze the expression of NLRP12 and key factors associated with canonical and non-canonical NF-κB pathways. Results indicated an increase in migratory and invasive capabilities, concurrent with heightened expression of IL-33, CXCL12, CXCL13, and factors associated with both canonical and non-canonical NF-κB pathways. Moreover, mRNA and protein levels of NLRP12 were decreased in BPDE-stimulated A549 cells. Subsequent SFN intervention attenuated BPDE-induced migration and invasion of A549 cells. Lentivirus-mediated NLRP12 overexpression not only reversed the observed phenotype in BPDE-induced cells but also led to a reduction in the expression of critical factors associated with both canonical and non-canonical NF-κB pathways. Collectively, we found that SFN could inhibit BPDE-induced migration and invasion of A549 cells by upregulating NLRP12, thereby influencing both canonical and non-canonical NF-κB pathways.

Cholinergic drugs reduce metabolic inflammation and diabetic myocardial injury by regulating the gut bacterial component lipopolysaccharide-induced ERK/Egr-1 pathway.

Autonomic imbalance and metabolic inflammation are important pathological processes in diabetic cardiomyopathy. Gut microbiota dysbiosis and increased levels of bacterial component lipopolysaccharide (LPS) are associated with diabetic myocardial injury, but the mechanism by which gut microbes affect metabolic inflammation and cardiac injury remains unclear. We determined whether pyridostigmine (PYR), which inhibits cholinesterase to improve vagal activity, could regulate the disordered gut microbiota and attenuate gut barrier dysfunction, metabolic endotoxemia, and inflammation in diabetes. Db/db mice exhibited high blood glucose levels, insulin resistance, low vagal activity, and diabetic myocardial injury. Db/db mice also exhibited gut microbiota perturbations and subsequent disruption of gut barrier function, resulting in an influx of LPS, metabolic endotoxemia, and inflammation. PYR ameliorated the dysregulated glucose and lipid metabolism, modulated the overall structure of the gut microbiota, selectively enhanced the abundance of anti-inflammatory bacteria, and reduced the abundance of proinflammatory and potentially pathogenic bacteria in db/db mice. Importantly, PYR enhanced vagal activity, restored gut microbiota homeostasis, and alleviated gut barrier dysfunction. Therefore, the LPS-induced extracellular signal-regulated kinase (ERK)/early growth response-1 (Egr-1) pathway and consequent metabolic inflammation were inhibited, and eventually, cardiac hypertrophy, fibrosis, oxidative stress, and dysfunction were ameliorated in db/db mice. In vitro cardiomyocyte injury was induced by exposing primary neonatal rat ventricular cardiomyocytes to high glucose (HG) and LPS. In vitro analyses showed that HG + LPS induced ERK1/2 phosphorylation, Egr-1 expression, inflammation, and cell apoptosis, which were inhibited by acetylcholine (ACh). Alpha 7 nicotinic ACh receptor but not muscarinic 2 ACh receptor plays an important role in ACh-mediated anti-inflammatory effects and inhibiting the ERK/Egr-1 pathway in HG + LPS-administered neonatal rat ventricular cardiomyocytes. PYR and ACh ameliorated diabetic myocardial injury by inhibiting the LPS-induced ERK/Egr-1 pathway and metabolic inflammation. The vagus-gut-heart axis has provided new insights into the complex mechanisms of diabetes and offers novel therapeutic targets.

Factors Associated with the First-time HIV Testing Among Chinese men who have sex with men Who Received HIV Self-tests from Partners or Friends.

Secondary distribution of HIV self-testing (HIVST) among individual social networks was an effective approach to expanding HIV testing among men who have sex with men (MSM). However, understanding the factors associated with first-time HIV testing behaviors in the secondary distribution of HIVST programs is limited. Hence, this study aims to identify factors related to first-time testers in the secondary distribution of HIVST. Participants were recruited from five provinces in southern China through Blued, a geo-social gay networking app in China from January 2021 to December 2021. Eligible consented participants (referred to as "seeds") finished a baseline survey and then applied for up to five HIVST kits. They were encouraged to distribute HIVST kits to other MSM (referred to as "alters") and alters were encouraged to scan a QR code to return their photographed testing results. All alters were invited to finish an online survey. In total, 229 seeds reached 292 alters, among whom 126 (43.2%) were first-time testers whereas 166 (56.8%) were non-first-time testers. Importantly, our results demonstrated that the first-time HIV testers were more likely to self-report as heterosexual (aOR = 4.88, 95% CI 1.01-23.61), disclose sexual orientation and/or SSB (aOR = 1.73, 95% CI 1.01-2.96), and receive HIVST knowledge from the seeds (aOR = 3.25, 95% CI 1.02-10.34). However, those who had sex with male partners in the last three months were less likely to be first-time testers (aOR = 0.43, 95% CI 0.23-0.82). Practical implications and limitations were also discussed to improve future HIV prevention programs.

Properties of biochar colloids and behaviors in the soil environment: Influencing the migration of heavy metals.

Biochar pyrolyzed by biomass shows excellent application prospects for heavy metal (HM) remediation, but a part of biochar can be inevitably broken into micro- and nano-sized biochar colloids (BCs) under biological and physicochemical actions in soil. BCs derived in the process of remediation have rough surface, rich elemental species and contents, and multiple functional groups, which are similar to biochar. However, BCs have some unique colloidal properties because of their micro and nano scale size. Due to these properties, BCs exhibit strong mobilities in the soil environment, and the mobilities may be influenced by a combination of colloidal properties of BCs and environmental factors including soil colloids and other soil environmental conditions. In addition, BCs may have affinity effects on HMs through electrostatic adsorption, ion exchange, surface complexation, precipitation/co-precipitation, and redox because of the properties such as large specific surface area, and rich oxygen-containing functional groups and minerals on the surface. This review summarizes the physicochemical and migratory properties of BCs, and the internal and external factors affecting the migration of BCs in the soil environment, and the possible effects of BCs on HMs are high-lighted. This review provides a theoretical basis for the optimization of soil contaminated with HMs after remediation using biochar. Notably, the innovative idea that BCs may influence the presence of HMs in soil needs to be further confirmed by more targeted detection and analysis methods in future studies to prevent the possible environmental toxicities of the lateral and vertical diffusion of HM caused by BCs in soil.

Efficient signal sequence of mRNA vaccines enhances the antigen expression to expand the immune protection against viral infection.

The signal sequence played a crucial role in the efficacy of mRNA vaccines against virus pandemic by influencing antigen translation. However, limited research had been conducted to compare and analyze the specific mechanisms involved. In this study, a novel approach was introduced by substituting the signal sequence of the mRNA antigen to enhance its immune response. Computational simulations demonstrated that various signal peptides differed in their binding capacities with the signal recognition particle (SRP) 54 M subunit, which positively correlated with antigen translation efficiency. Our data revealed that the signal sequences of tPA and IL-6-modified receptor binding domain (RBD) mRNA vaccines sequentially led to higher antigen expression and elicited more robust humoral and cellular immune protection against the SARS-CoV-2 compared to the original signal sequence. By highlighting the importance of the signal sequence, this research provided a foundational and safe approach for ongoing modifications in signal sequence-antigen design, aiming to optimize the efficacy of mRNA vaccines.

Technical variety of anastomotic techniques used in proximal gastrectomy with double-tract-reconstruction - a narrative review.

In the past 40 years, the incidence of esophagogastric junction cancer has been gradually increasing worldwide. Currently, surgical resection remains the main radical treatment for early gastric cancer. Due to the rise of functional preservation surgery, proximal gastrectomy has become an alternative to total gastrectomy for surgeons in Japan and South Korea. However, the methods of digestive tract reconstruction after proximal gastrectomy have not been fully unified. At present, the principal methods include esophagogastrostomy, double flap technique, jejunal interposition, and double tract reconstruction. Related studies have shown that double tract reconstruction has a good anti-reflux effect and improves postoperative nutritional prognosis, and it is expected to become a standard digestive tract reconstruction method after proximal gastrectomy. However, the optimal anastomoses mode in current double tract reconstruction is still controversial. This article aims to review the current status of double tract reconstruction and address the aforementioned issues.

Generation of SARS-CoV-2 reporter replicon for high-throughput antiviral screening and testing.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) research and antiviral discovery are hampered by the lack of a cell-based virus replication system that can be readily adopted without biosafety level 3 (BSL-3) restrictions. Here, the construction of a noninfectious SARS-CoV-2 reporter replicon and its application in deciphering viral replication mechanisms and evaluating SARS-CoV-2 inhibitors are presented. The replicon genome is replication competent but does not produce progeny virions. Its replication can be inhibited by RdRp mutations or by known SARS-CoV-2 antiviral compounds. Using this system, a high-throughput antiviral assay has also been developed. Significant differences in potencies of several SARS-CoV-2 inhibitors in different cell lines were observed, which highlight the challenges of discovering antivirals capable of inhibiting viral replication in vivo and the importance of testing compounds in multiple cell culture models. The generation of a SARS-CoV-2 replicon provides a powerful platform to expand the global research effort to combat COVID-19.

Ameliorative effects of zinc and vitamin E against phthalates-induced reproductive toxicity in male rats.

OBJECTIVE: Phthalates (PEs) could cause reproductive harm to males. A mixture of three widely used PEs (MPEs) was used to investigate the ameliorative effects of zinc (Zn) and vitamin E (VE) against male reproductive toxicity. METHODS: Fifty male SD rats were randomly divided into five groups (n = 10). Rats in MPEs group were orally treated with 160 mg/kg/d MPEs, while rats in MPEs combined Zn and/or VE groups were treated with 160 mg/kg/d MPEs plus 25 mg/kg/d Zn and/or 25 mg/kg/d VE. After intervention for 70 days, it's was measured of male reproductive organs' weight, histopathological observation of sperms and testes, serum hormones, PIWI proteins and steroidogenic proteins. RESULTS: Compared with control, anogenital distance, testes weight, epididymides weight, and sex hormones were significantly decreased, while the sperm malformation rate was markedly increased in MPEs group (p < .05); the testicular tissues were injured in MPEs group with disordered and decreased spermatids, and arrested spermatogenesis. PIWIL1, PIWIL2, StAR, CYP11A1 and CYP19A1 were down-regulated in MPEs group (p < .05). However, the alterations of these parameters were restored in MPEs combined Zn and/or VE groups (p < .05). CONCLUSION: Zn and/or VE improved steroid hormone metabolism, and inhibited MPEs' male reproductive toxicity.